Organic electroluminescence device

ABSTRACT

An electroluminescence device comprising, as a light emitting material, a compound of the formula: ##STR1## wherein R 1  and R 2  are each an alkyl, cyclohexyl, alkoxy, cyano or aryl, R 3  and R 4  are a heterocyclic or aryl and Ar is an arylene. Aromatic dimethylidyne compounds of the formula: ##STR2## wherein X and Y are each an alkyl, phenyl, cyclohexyl, naphthyl or pyridyl and Ar&#39; is ##STR3## Electroluminescence devices (EL devices) using the above compounds as a light emitting material provide EL light emission of high luminance in a region of bluish purple to green.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a novel electroluminescence (EL) deviceand more particularly to an organic EL device capable of emitting lightin a region of bluish purple to green at a high luminance and in astabilized manner. Moreover, the present invention relates to novelaromatic dimethylidyne compounds useful, for example, as emittingmaterials for an EL device, processes for efficiently preparing theabove compounds, and an EL device using the above compound.

2. Description of the Related Arts

A device utilizing EL performance of an organic compound has been longstudied in view of fluorescence of the organic compound. For example, W.Helfrish, Dresmer, Williams et al. succeeded in emission of blue lightusing anthracene crystal (J. Chem. Phys. 44, 2902 (1966)). Vincett,Barlow, et al. produced a light emitting device by a vapor depositionmethod, using a condensed polycyclic aromatic compound (Thin SolidFilms, 94, 171 (1982)).

However, only a light emitting device low in luminance and luminousefficiency has been obtained.

It is reported that emission of blue light of 100 cd/m² was obtainedusing tetraphenylbutadiene as a light emitting material (Japanese PatentApplication Laid-Open No. 194393/1984). In practice, however, theefficiency is markedly low and is unsatisfactory.

It is reported that a green light emitting organic thin film EL deviceproviding the maximum luminance of more than 1,000 cd/m² and anefficiency of 1 lm/W was developed by laminating a diamine compoundconveying a hole and a luminous aluminum chelate complex as a lightemitting material (Appl. Phys. Lett., 51, 913 (1987)).

It is also reported that a distyrylbenzene compound well known as alaser dye exhibits high fluorescent properties in the region of blue toblue green, and a light emitting material using the distyrylbenzenecompound in a single layer form emits EL light of about 80 cd/m²(European Patent 0319881).

However, a light emitting material providing light other than greenlight (particularly blue-based light) in a luminance as high as morethan 1,000 cd/m² and with high efficiency has not been obtained.

In connection with the structure of the aforementioned organic ELdevice, those obtained by properly providing a hole injection layer oran electron injection layer into a basic structure having a positiveelectrode/light emitting layer/negative electrode, e.g., a structure ofpositive electrode/hole injection layer/light emitting layer/negativeelectrode, or a structure of positive electrode/hole injectionlayer/light emitting layer/electron injection layer/negative electrodeare known. The hole injection layer functions to inject a hole into thelight emitting layer from the positive electrode, and the electroninjection layer, to inject an electron into the light emitting layerfrom the negative electrode. It is known that placing the hole injectionlayer between the light emitting layer and the positive electrodepermits injection of more holes at a lower voltage, and that electronsinjected from the negative electrode or the injection layer into thelight emitting layer are accumulated at the light emitting layer side inan interface between the light emitting layer and the hole injectionlayer when the hole injection layer does not have electron transportingability, increasing a luminous efficiency (Applied Physics Letters, Vol.51, p. 913 (1987)).

As such organic EL devices, for example, (1) a laminate type EL devicehaving a structure of positive electrode/hole injection layer/lightemitting layer/negative electrode in which the light emitting layer ismade of an aluminum complex of 8-hydroxyquinoline, and the holeinjection layer, of a diamine compound (Appl. Phys. Lett., Vol. 51, p.913 (1987)), (2) a laminate type EL device having a structure ofpositive electrode/hole injection zone/organic light emittingzone/negative electrode in which an aluminum complex of8-hydroxyquinoline is used in preparation of the light emitting zone(Japanese Patent Application Laid-Open No. 194393/1984), and (3) an ELdevice having a structure of positive electrode/hole injectionzone/light emitting zone/negative electrode in which the light emittingzone is made of a host material and a fluorescent material (EuropeanPatent Publication No. 281381) are known.

In the above EL devices (1) and (2), although light emission of highluminance is attained at a low voltage, it is necessary to control thetemperature of a vapor deposition source not to be more than 300° C.,i.e., as low as nearly an evaporation temperature in vapor deposition,because an aluminum complex of 8-hydroxyquinoline when used as a lightemitting material is readily decomposable at a temperature of more thanabout 300° C. It is therefore difficult to control conditions forproduction of a device and, moreover, vapor deposition speed isdecreased. Thus the devices (1) and (2) inevitably suffer from a problemof a reduction in productivity of devices. Moreover the aluminum complexof 8-hydroxyquinoline can emit green light, but not blue light.

In the EL device (3), a compound capable of injecting a hole and aelectron from the outside, preferably an aluminum complex of8-hydroxyquinoline is used as a host material, and as a fluorescentmaterial, a compound capable of emitting light in response tore-combination of a hole and an electron, such as a known fluorescentdye.

In this device, among an injection function (function to inject a holefrom either a positive electrode or a hole injection layer and also toinject an electron either from an electrode or a negative electroninjection layer, upon application of electric field), a transportfunction (function to transport a hole and an electron upon applicationof electric field), and a light emitting function (function to provide afield for recombination of a positive hole and an electron, therebyproducing light emission), the light emitting zone (light emittinglayer) should have the injection function, the transport function, andpart of the light emitting function fulfilled by the host material,while only part of the light emitting function is fulfilled by thefluorescent material. For this reason, the host material is doped with avery small amount (not more than 5 mol %) of the fluorescent material.An EL device of the above structure can emit light in the region of fromgreen to red at a luminance as high as above 1,000 cd/m² by applicationof a voltage of about 10 V.

In this EL device, however, the same problems as in the above EL devices(1) and (2) are encountered, because it usually uses8-hydroxyquinoline-Al complex as a host material. Moreover, it isimpossible to emit light of a short wavelength having a higher energythan the energy gap value of the 8-hydroxyquinone from a fluorescentmaterial; emission of blue light cannot be obtained.

As described above, the above devices (1), (2) and (3) cannot provideblue light emission of high luminance in a stabilized manner and withhigh efficiency. However, they provides an epoch making technicaladvance by showing that a high luminous and high efficiency EL devicecan be realized by selecting a light emitting material with a structureof positive electrode/hole injection layer made of aminoderivative/light emitting layer/negative electrode. In this selection ofthe light emitting material, the three functions of the above lightemitting layer should be satisfied. Moreover it should be taken intoconsideration that a material with excellent film forming properties asa light emitting layer should be selected. Moreover the materialselected should have excellent heat resistance properties and shouldavoid decomposition at the time of heating for vacuum deposition. It hasbeen difficult to find a light emitting material to satisfy all theabove requirements. Thus the present inventors made extensiveinvestigations to develop a compound providing light emission in aregion of bluish purple to green, particularly in a blue region at ahigh luminance and with high efficiency.

The present inventors made extensive investigations to attain the aboveobjects. As a result, they have found that stilbene-based compoundshaving specified structures have an injection ability, a transportingability and a light emitting ability essential for a light emittinglayer, are excellent in heat resistance and thin film formingproperties, are free from decomposition even if heated to a vacuumdeposition temperature, can form a uniform and dense film havingexcellent thin film forming properties, and moreover are rarely subjectto formation of pinholes at the time of formation of the oppositeelectrode (metal), and that if the above compounds are used as lightemitting materials, an EL device can be obtained with high efficiencyand moreover the EL device provides stable light emission of highluminance from bluish purple to green upon application of a low voltage.Based on the findings, these present invention has been accomplished.Furthermore, the EL device is of high efficiency in a practical luminousregion (80 to 200 cd/m²).

SUMMARY OF THE INVENTION

An object of the present invention is to provide an EL device of highstability and providing a luminance of 1,000 cd/m² or more in blue lightregion.

Another object of the present invention is to provide an EL device ofhigh efficiency in a practical luminous region.

Some of the light emitting materials of the present invention are novelcompounds.

Another object of the present invention is to provide such novelaromatic dimethylidyne compounds.

Another object of the present invention is to provide a process forefficiently preparing the above novel aromatic dimethylidyne compound.

That is, the present invention provides an EL device using as a lightemitting material a compound represented by the general formula:##STR4## (wherein R¹ and R² are each an alkyl group, a substituted orunsubstituted cyclohexyl group, an alkoxy group, a cyano group, or asubstituted or unsubstituted aryl group, R³ and R⁴ are each asubstituted or unsubstituted heterocyclic group, or an aryl group, Ar isa substituted or unsubstituted arylene group, and R¹ and R³, and R² andR⁴ may combine together to form a substituted or unsubstituted,saturated or unsaturated ring structure).

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will hereinafter be explained in detail.

In the EL device of the present invention, as a light emitting material,a compound represented by the general formula: ##STR5## (wherein R¹ ,R², R³, R⁴ and Ar have the same meanings as above) is used.

These compounds have a skeleton similar to that of distyrylbenzene, havefluorescent properties in a solid state, and have the characteristicsthat mobility of electron and positive hole is good, ionization energyis small owing to the conjugated properties of the skeleton similar tothat of distyrylbenzene, and injection of electric charge from anelectrode, for example, is easy because of high electron affinity.

In the above general formula (I), R¹ and R² are each an alkyl group,such as a methyl group, an ethyl group, a propyl group or a butyl group,a substituted or unsubstituted cyclohexyl group, an alkoxy group, suchas a methoxy group, an ethoxy group, a propoxy group or a butoxy group,a cyano group, or an aryl group. This aryl group includes phenyl,naphthyl, anthranyl and the like, and may or may not be substituted bythe various groups shown below. Various substituents can be introducedinto the aryl group as long as they do not deteriorate the abovecharacteristics. Examples are a halogen atom, an alkyl group such as amethyl group, an ethyl group, a propyl group or a butyl group, an alkoxygroup such as a methoxy group, an ethoxy group, a propoxy group or abutoxy group, an acyl group such as a formyl group, an acetyl group, apropionyl group or a butylyl group, an acyloxy group such as anacetyloxy group, a propionyloxy group or a butylyloxy group, an acylamino group such as acetylamino group, a propionylamino group or abutylylamino group, an aralkyl group such as a phenoxy group or atolyloxy group, a cyano group, a carboxyl group, a vinyl group, a styrylgroup, an aminocarbonyl group such as an anilinocarbonyl group, adimethylaminocarbonyl group, a carbamoyl group or an aranyl group, ahydroxyl group, an aryloxycarbonyl group such as a naphthyloxycarbonylgroup, a xylyloxycarbonyl group or a phenoxycarbonyl group, analkoxycarbonyl group such as a methoxycarbonyl group, an ethoxycarbonylgroup or a butoxycarbonyl group, and an amino group represented by thegeneral formula: ##STR6## (wherein R⁵ and R⁶ are each a hydrogen atom,an alkyl group such as a methyl group, an ethyl group, a propyl group ora butyl group, an acyl group such as a formyl group, an acetyl group ora propionyl group, an aldehyde group, a phenyl group, or a substitutedphenyl group such as a tolyl group or a xylyl group, and may be the sameor different, and may combine together to form a substituted orunsubstituted 5-membered or 6-membered ring, and may combine withanother group on the aryl group to form a substituted or unsubstituted,saturated 5-membered ring or saturated 6-membered ring). R¹ and R² maybe the same or different.

Substituents on the aryl group may combine together to form asubstituted or unsubstituted, saturated 5-membered or 6-membered ring.

R³ and R⁴ in the above general formula (I) are each a heterocyclic ringor an aryl group such as phenyl, naphthyl or anthranyl, and may besubstituted or unsubstituted. Examples of the heterocyclic group are apyridyl group, an oxazolyl group, a thienyl group, an imidazolyl group,a thiazolyl group, a benzoimidazolyl group, a benzothiazolyl group, apyrazolyl group, a triazolyl group, a monovalent group comprisingpyridone, a furaryl group, a benzoxazolyl group, and a quinolyl group.Substituents which the aryl group or the heterocyclic ring can have arethe same as those cited above for the aryl group of R¹ and R². R³ and R⁴may be the same or different.

R¹ and R³ may combine together to form a substituted or unsubstituted,saturated or unsaturated ring structure, and R² and R⁴ may combinetogether to form a substituted or unsubstituted, saturated orunsaturated ring structure.

Ar in the above general formula (I) is an arylene group and may besubstituted or unsubstituted. As the substituents, various groups may beintroduced within a range that does not deteriorate the abovecharacteristics. Examples are a halogen atom, an alkyl group such as amethyl group, an ethyl group, a propyl group, a butyl group or acyclohexyl group, an alkoxy group such as a methoxy group, an ethoxygroup, a propoxy group or a butoxy group, an acyl group such as a formylgroup, an acetyl group, a propionyl group or a butyryl group, an acyloxygroup such as an acetyloxy group, a propionyloxy group, or a butylyloxygroup, an aralkyl group such as a benzyl group or a phenethyl group, anaryloxy group such as a phenoxy group or a tolyloxy group, a cyanogroup, a carboxyl group, an aminocarbonyl group such as ananilinocarbonyl group, a dimethylaminocarbonyl group, a carbamoyl groupor an aranyl group, a hydroxyl group, an aryloxycarbonyl group such as aphenoxycarbonyl group, a naphthyloxycarbonyl group or a xylyloxycarbonylgroup, a methoxycarbonyl group, an ethoxycarbonyl group, abutoxycarbonyl group, and the amino groups represented by the abovegeneral formula (I).

Substituents on the arylene group may combine together to form asubstituted or unsubstituted, saturated 5-membered or 6-membered ring.

The compounds represented by the above general formula (I) can beprepared by various methods; for example, the Wittig method is suitable.

Representative examples of the compounds represented by the generalformula (I) are shown below. ##STR7##

The novel aromatic dimethylidyne compound of the present invention isrepresented by the general formula (II): ##STR8##

This aromatic dimethylidyne compound contains an arylene group (Ar') inthe center thereof and also two substituents (X, Y) at both terminalswhich are symmetrical with respect to the central arylene group.

X and Y in the general formula (II) may be, as described above, the sameor different and are independently an alkyl group having 1 to 4 carbonatoms (a methyl group, an ethyl group, a n-propyl group, an i-propylgroup, a n-butyl group, an i-butyl group, a sec-butyl group, and atert-butyl group), a phenyl group, a cyclohexyl group, a naphthyl group,or a pyridyl group. X and Y may be substituted; that is, X and Y furtherrepresent substituted phenyl groups, substituted cyclohexyl groups,substituted naphthyl group, or substituted pyridyl groups. In thesegroups, the substituent is an alkyl group having 1 to 4 carbon atoms, analkoxy group having 1 to 4 carbon atoms, or a phenyl group. The abovesubstituted groups may be substituted by two or more substituents. Thusthe substituted phenyl group includes an alkyl group-substituted phenylgroup (e.g., a tolyl group, a dimethylphenyl group, or an ethylphenylgroup), an alkoxy-substituted phenyl group (e.g., a methoxyphenyl groupor an ethoxyphenyl group), and phenyl-substituted phenyl group (i.e., abiphenyl group). The substituted cyclohexyl group includes an alkylgroup-substituted cyclohexyl group (e.g., a methylcyclohexyl group, adimethylcyclohexyl group, or an ethylcyclohexyl group), an alkoxygroup-substituted cyclohexyl group (e.g., a methoxycyclohexyl group, oran ethoxycyclohexyl group), and a phenyl group-substituted cyclohexylgroup (phenylcyclohexyl group). The substituted naphthyl group includesan alkyl group-substituted naphthyl group (e.g., a methylnaphthyl group,or a dimethylnaphthyl group), an alkoxy group-substituted naphthyl group(e.g., a methoxynaphthyl group, or an ethoxynaphtyl group), and a phenylgroup-substituted naphthyl group. The substituted pyridyl group includesan alkyl group-substituted pyridyl group (e.g., a methyl pyridyl group,a dimethylpyridyl group, or an ethylpyridyl group), an alkoxygroup-substituted pyridyl group (e.g., a methoxypyridyl group, or anethoxypyridyl group), and a phenyl group-substituted pyridyl group.

X and Y are preferred to be independently a methyl group, a phenylgroup, a naphthyl group, a pyridyl group, a cyclohexyl group, a tolylgroup, a methoxyphenyl group, or a biphenyl group.

Ar' in the general formula (II) is an alkyl-substituted arylene group,including a methyl-substituted arylene group, an ethyl-substitutedarylene group, a propyl-substituted arylene group, and abutyl-substituted arylene group. Examples are shown below. ##STR9##

The novel aromatic dimethylidyne compound of the present invention asdescribed above can be prepared by various methods: it can be preparedwith efficiency particularly by the process A or B of the presentinvention.

In accordance with the process A of the present invention, an arylenegroup-containing phosphorus compound represented by the aforementionedgeneral formula (III): ##STR10## (wherein R is an alkyl group having 1to 4 carbon atoms and Ar' is the same as defined above) and a ketonecompound represented by the general formula (IV): ##STR11## (wherein X'and Y' are the same as X and Y defined above, respectively, providedthat an alkyl group having 1 to 4 carbon atoms are excluded) iscondensed to prepare the desired aromatic dimethylidyne compound of thegeneral formula (II'). ##STR12## (wherein X', Y' and Ar' are the same asdefined above).

Ar' in the general formula (III) corresponds to Ar' of an aromaticdimethylidyne compound to be prepared. R is an alkyl group having 1 to 4carbon atoms (e.g., a methyl group, an ethyl group, a propyl group, or abutyl group).

This arylene group-containing phosphorus compound can be obtained by aknown method, such as by reacting an aromatic bishalomethyl compoundrepresented by the general formula:

    X.sup.2 H.sub.2 C--Ar'--CH.sub.2 X.sup.2

(wherein X² is a halogen atom, and Ar' is the same as defined above) andtrialkyl phosphite represented by the general formula:

    (RO).sub.3 P

(wherein R is the same as defined above).

In the ketone compound of the general formula (IV), X¹ and Y¹ are chosencorresponding to X¹ and Y¹ of an aromatic dimethylidyne compound to beprepared. X¹ and Y¹ are the same as X and Y as described above(excluding an alkyl group having 1 to 4 carbon atoms).

A condensation reaction of an arylene group-containing phosphoruscompound of the general formula (III) and a ketone compound of thegeneral formula (IV) can be carried out under various conditions.

Preferred examples of solvents which can be used in the above reactionare hydrocarbons, alcohols and ether. Representative examples aremethanol, ethanol, isopropanol, butanol, 2-methoxy ethanol,1,2-dimethoxy ethanol, bis(2-methoxyethyl) ether, dioxane,tetrahydrofuran, toluene, xylene, dimethylsulfoide,N,N-dimethylformamide, N-methylpyrrolidone, and1,3-dimethyl-2-imidazolidinone. Of these solvents, tetrahydrofuran isparticularly preferred.

In the reaction, as a condensing agent, sodium hydroxide, potassiumhydroxide, sodium amide, sodium hydride, n-butyl lithium, or alcolatesuch as sodium methylate or potassium tert-butoxide is used ifnecessary. Of these compounds, n-butyl lithium is preferred.

The reaction temperature varies with the type of the starting materialand other conditions, and cannot be determined unconditionally. Usuallythe reaction temperature is chosen from a wide range of about 0° to 100°C., with the range of 10° to 70° C. being particularly preferred.

The aromatic dimethylidynes of the present invention can be preparedefficiently by the above process A. Some of the aromatic dimethylidynecompounds can be prepared efficiently also by the process B.

In accordance with the process B, a phosphorus compound of the generalformula (V): ##STR13## (wherein X, Y and R are the same as definedabove) and a dialdehyde compound of the general formula (VI):

    OHC--Ar'--CHO                                              (VI)

(wherein Ar' is the same as defined above) are subjected to acondensation reaction to prepare the objective aromatic dimethylidynecompound of the general formula (II).

In the general formula (V), R is an alkyl group having 1 to 4 carbonatoms (e.g., a methyl group, an ethyl group, a propyl group, or a butylgroup). X and Y are correspondent to X and Y of an aromaticdimethylidyne compound to be prepared.

In the general formula (VI), Ar' corresponds to Ar' of an aromaticdimethylidyne compound to be prepared.

The condensation reaction of a phosphorus compound of the generalformula (V) and a dialdehyde compound of the general formula (VI) can becarried out under various conditions. Solvents and condensing agentspreferably used in the reaction are the same as in the process A.

The reaction temperature varies with the type of the starting materialand other conditions, and cannot be determined unconditionally. Usuallythe reaction temperature is chosen from a wide range of about 0° to 100°C., with the range of 0° C. to room temperature being particularlypreferred.

The aromatic dimethylidyne compounds of the present invention can beprepared efficiently by the process A and also by the process B.

The aromatic dimethylidyne compound of the present invention can beutilized in production of an EL device capable of emitting light of highluminance at a low voltage.

The aromatic dimethylidyne compound of the present invention possessesan electric charge injection function, an electric charge transportfunction, and a light emitting function which are essential for a lightemitting material of an EL device, and furthermore is excellent in heatresistance and thin film forming properties.

Moreover the aromatic dimethylidyne compound of the present inventionhas the advantages of being free from decomposition or degradation evenif heated to its vapor deposition temperature, forming a uniform anddense film, and being free from formation of pinholes. Thus they can besuitably used in various devices other than the EL device.

The aromatic dimethylidyne compound of the present invention is, asdescribed above, effectively used as light emitting materials of an ELdevice. This light emitting layer can be produced by forming a thin filmof light emitting material, for example, by forming a thin film of acompound of the general formula (I) or (II) by known techniques such asa vacuum evaporation method, a spin coating method, or a casting method.It is particularly preferred that the compound of the general formula(I) or (II) be formed into a molecular accumulated film. The molecularaccumulated film as used herein refers to a thin film formed bydepositing a compound from the gaseous state, or a thin film formed bysolidification from the solution or liquid state. An example of themolecular accumulated film is a vacuum evaporated film. Usually themolecular accumulated film can be distinguished from a thin film(molecular accumulated film) formed by a LB method.

The light emitting layer can be formed by dissolving a binder, such as aresin, and the compound in a solvent to prepare a solution, and formingthe solution into a thin film by a spin coating method.

The thickness of the thin film as the light emitting layer as thusformed is not critical and can be determined appropriately. Usually thethickness is chosen from a range of 5 nm to 5 μm.

The light emitting layer of the organic EL device is required to have,for example, (1) an injection function to inject a hole from a positiveelectrode or a hole injection layer, and to inject an electron from anegative electrode or an electron injection layer, upon application ofan electric field, (2) a transport function to move the charge injected(electron and positive hole) by the force of electric field, and (3) alight emitting function to provide a field for recombination of anelectron and a hole, thereby causing light emission.

Although ease of injection of hole and ease of injection of electron maybe different from each other, and the transport abilities of hole andelectron as indicated by their mobilities may be different from eachother, it is preferred that one of the charges be transported.

Since the ionization potential of the compound of the general formula(I) to be used in the light emitting layer is usually less than about6.0 eV, positive holes can be injected relatively easily by choosing aproper metal or compound as the positive electrode. Since the electronaffinity of the compound of the general formula (I) is larger than about2.8 eV, if a proper metal or compound is chosen as the negativeelectrode, electrons can be injected relatively easily, and moreover anability to transport electrons and holes is excellent. Moreover, thecompound of the general formula (I) has a great ability to convert anexcited state formed in the compound, or its associated compound, or itscrystal at the time of re-combination of electron and hole, into light,because it has strong fluorescence in a solid state.

In connection with the structure of the EL device using the aromaticdimethylidyne compound of the present invention, there are variousembodiments. Basically the EL device comprises a pair of electrodes(positive electrode and negative electrode) and the above light emittinglayer sandwiched therebetween, with a hole injection layer and anelectron injection layer being inserted if necessary. Specific examplesof the structures are: (1) positive electrode/light emittinglayer/negative electrode; (2) positive electrode/hole injectionlayer/light emitting layer/negative electrode; and (3) positiveelectrode/hole injection layer/light emitting layer/electron injectionlayer/negative electrode. Although the hole injection layer and theelectron injection layer are not always needed, they markedly increaselight emitting performance if provided.

The EL device of the above structure is preferably supported on asubstrate. There are no special limitations to the substrate; substratescommonly used in production of EL devices, such as glass, transparentplastics, or quartz can be used.

As the positive electrode of the EL device, an electrode made of ametal, an alloy, an electrically conductive compound or a mixturethereof, having a large work function (at least about 4 eV) ispreferably used. Specified examples of such materials for the electrodeinclude metals, e.g., Au, and electrically conductive transparentcompounds, e.g., CuI, ITO, SnO₂, and ZnO. The positive electrode can beproduced by forming a thin film of the above material by a method suchas vacuum evaporation or sputtering. For light emission from theelectrode, it is preferred that the transmittance be more than 10%, andthe sheet resistance as an electrode be less than several hundred ohmsper millimeter (Ω/□). The film thickness is usually from 10 nm to 1 μmand preferably from 10 to 200 nm, although it varies with the type ofthe material used.

As the negative electrode, an electrode made of a metal, an alloy, anelectrically conductive compound or a mixture thereof, having a smallwork function (less than about 4 eV) is used. Specific examples of suchmaterials for the negative electrode include sodium, a sodium-potassiumalloy, magnesium, lithium, a magnesium/second metal mixture, Al/AlO₂,and indium. The negative electrode can be produced by forming a thinfilm of the above material by a method such as vacuum evaporation(vacuum deposition) or sputtering. The sheet resistance as an electrodeis preferably less than several hundred ohms per millimeter (Ω/□), andthe film thickness is usually 10 nm to 1 μm and preferably 50 to 200 nm.

In the EL device, the positive electrode or the negative electrode ispreferably transparent or translucent, in view of a high efficiency ofwithdrawing light emitted, because a transparent or translucentelectrode transmits light.

In connection with the structure of the EL device using the aromaticdimethylidyne compound of the present invention, as described above,there are a variety of embodiments. In the EL device of the abovestructures (2) and (3), the hole injection layer (positive holeinjection transport layer) is a layer of a hole transporting compoundand has a function to transport a hole injected from the positiveelectrode to the light emitting layer. If the hole injection layer isplaced between the positive electrode and the light emitting layer, moreholes are injected into the light emitting layer at a lower electricfield and, moreover, electrons injected from the negative electrode orthe electron injection layer into the light emitting layer areaccumulated in the vicinity of interface between the hole injectionlayer and the light emitting layer in the light emitting layer when thepositive hole injection layer does not have electron transportcapability, thereby increasing a luminous efficiency. Thus a deviceexcellent in light emitting performance is obtained.

As the hole transporting compound to be used in the above hole injectionlayer, a compound capable of transporting holes properly when placedbetween two electrodes between which an electric field is applied, andthe holes are injected from the positive electrode, and having a holemobility of at least 10⁻⁶ cm² /V.sec when an electric field of 10⁴ to10⁶ V/cm is applied is suitably used.

There are no special limitations to the hole transporting compound aslong as it has preferred properties as described above. Known compoundsconventionally used as hole transporting material in photoconductivematerials, or used in the hole injection layer of the EL device can beused.

Electric charge transporting materials which can be used includetriazole derivatives (described in U.S. Pat. No. 3,112,197, etc.),oxadiazole derivatives (described in U.S. Pat. No. 3,189,447, etc.),imidazole derivatives (described in Japanese Patent Publication No.16096/1962, et.), polyaryl alkane derivatives (described in U.S. Pat.Nos. 3,615,402, 3,820,989, 3,542,544, Japanese Patent Publication Nos.555/1970, 10983/1976, Japanese Patent Application Laid-Open Nos.93224/1976, 17105/1980, 4148/1981, 108667/1980, 156953/1980, 36656/1981,etc.), pyrazoline derivatives and pyrazolone derivatives (described inU.S. Pat. Nos. 3,180,729, 4,278,746, 88064/1980, 88065/1980,105537/1974, 51086/1980, 80051/1981, 88141/1981, 45545/1982,112637/1979, 74546/1980, etc.), phenylenediamine derivatives (describedin U.S. Pat. No. 3,615,404, Japanese Patent Publication Nos. 10105/1976,3712/1971, 25336/1972, Japanese Patent Application Laid-Open Nos.53435/1979, 110536/1979, 119925/1979, etc.), arylamine derivatives(described in U.S. Pat. Nos. 3,567,450, 3,180,703, 3,240,597, 3,658,520,4,232,103, 4,175,961, 4,012,376, Japanese Patent Publication Nos.35702/1974, 27577/1964, Japanese Patent Application Laid-Open Nos.144250/1980, 119132/1981, 22437/1981, West German Patent 1,110,518,etc.), amino substituted calcon derivatives (described in U.S. Pat. No.3,526,501, etc.), oxazole derivatives (described in U.S. Pat. No.3,257,203, etc.), styrylanthracene derivatives (described in JapanesePatent Application Laid-Open No. 46234/1981, etc.), fluorenonederivatives (described in Japanese Patent Application Laid-Open No.110837/1979, etc.), hydrazone derivatives (described in U.S. Pat. No.3,717,462, Japanese Patent Application Laid-Open Nos. 59143/1979,52063/1980, 52064/1980, 46760/1980, 85495/1980, 11350/1972, 148749/1972,etc.), stilbene derivatives (described in Japanese Patent ApplicationLaid-Open Nos. 210363/1986, 228451/1986, 14642/1986, 72255/1986,47646/1987, 36674/1987, 10652/1987, 30255/1987, 93445/1985, 94462/1985,174749/1985, 175052/1985, etc.), and the like.

Although these compounds can be used as hole transporting compounds,porphyrin compounds (described in Japanese Patent Application Laid-OpenNo. 295695/1978, etc.) and aromatic tertiary amine compounds asdescribed hereinafter, and styrylamine compounds (described in U.S. Pat.No. 4,127,412, Japanese Patent Application Laid-Open Nos. 27033/1978,58445/1979, 149631/1979, 64299/1979, 79450/1980, 144250/1980,119132/1981, 295558/1986, 98353/1986, 295695/1978, etc.) are preferablyused. Of these compounds, the aromatic tertiary amine compounds areparticularly preferred.

Typical examples of the porphyrin compound are porphyrin, copper (II)1,10,15,20-tetraphenyl-21H,23H-porphyrin, zinc (II)1,10,15,20-tetraphenyl-21H,23H-porphyrin,5,10,15,20-tetrakis(pentaflurophenyl)-21H,23H-porphyrin,siliconphthalocyanine oxide, aluminum phthalocyanine chloride,phthalocyanine (no metal), dilithium phthalocyanine, coppertetramethylphthalocyanine, copper phthalocyanine, chromiumphthalocyanine, zinc phthalocyanine, lead phthalocyanine, titaniumphthalocyanine oxide, magnesium phthalocyanine, and copperoctamethylphthalocyanine.

Typical examples of the aromatic tertiary amine compound and thestyrylamine compound are N,N,N',N'-tetraphenyl-4,4'-diaminobiphenyl,N,N'-diphenyl-N,N'-di(3-methylphenyl)-4,4'-diaminobiphenyl,2,2-bis(4-di-p-tolylaminophenyl)propane,1-bis(4-di-p-tolylaminophenyl)cyclohexane,N,N,N',N'-tetra-p-tolyl-4,4'-diaminobiphenyl,1,1-bis(4-di-p-tolylaminophenyl)-4-phenylcyclohexane,bis(4-dimethylamino-2-methylphenyl)phenylmethane,bis(4-di-p-tolylaminophenyl)phenylmethane,N,N'-diphenyl-N,N'-di(4-methoxyphenyl)-4,4'-diaminobiphenyl,N,N,N',N'-tetraphenyl-4,4'-diaminodiphenyl ether,4,4'-bis(diphenylamino) quadriphenyl, N,N,N-tri(p-tolyl)amine,4-(di-p-tolylamine)- 4'-[4(di-p-tolyamine)styryl]stilbene,4-N,N-diphenylamino-(2-diphenylvinyl)benzene,3-methoxy-4'-N,N-diphenylaminostilbene, and N-phenylcarbozole.

The hole injection layer of the above EL device may be a single layer ofone or more of the above hole transporting compounds, or may be alaminate of a layer of one or more of the above hole transportingcompounds, and a layer of other hole transporting compounds.

The electron injection layer (electron injection transport layer) in theEL device of the above structure (3) is made of an electron transportingcompound and has a function to transport electrons injected from thenegative electrode to the light emitting layer.

There are no special limitations to the electron transporting compoundto be used; a suitable one selected from the conventionally knowncompounds can be used.

Preferred examples of the electron transporting compound includenitro-substituted fluorenone derivatives having the formulas: ##STR14##thiopyrandioxide derivatives having the formula: diphenoquinonederivative having the formula: (described in Polymer Preprints, Japan,Vol, 37, No. 3, p. 681 (1988)), compounds having the formula: ##STR15##(described in Journal of Applied Physics, Vol. 27, p. 269 (1988) etc.),anthraquinonodimethane derivatives (described in Japanese PatentApplication Laid-Open Nos. 149259/1982, 55450/1983, 225151/1986,233750/1986, 104061/1988, etc.), fluoroenyldenemethane derivatives(described in Japanese Patent Application Laid-Open Nos. 69657/1985,143764/1986, 148159/1986, etc.), anthrone derivatives (described inJapanese Patent Application Laid-Open Nos. 225151/1976, 233750/1986,etc.), and a compound having the formula: ##STR16##

A suitable example of the process for production of an EL device usingan aromatic dimethylidyne compound of the present invention willhereinafter be explained.

First, a process for production of an EL device comprising positiveelectrode/light emitting layer/negative electrode as described above isexplained.

A thin film of a desired electrode material, for example, a substancefor positive electrode is formed on a suitable substrate in a thicknessof not more than 1 μm, preferably 10 to 200 nm by a method such asvacuum evaporation or sputtering to provide a positive electrode. Onthis positive electrode, a thin film of a compound of the generalformula (I) as a light emitting material is formed to provide a lightemitting layer. For production of the thin film of the light emittingmaterial, a spin coating method, a costing method, or a vacuumevaporation method, for example, can be employed. Of these methods, thevacuum evaporation method is preferred in that a uniform film can beeasily obtained, and pinholes are less formed.

When the vacuum evaporation method is employed in formation of the thinfilm of the light emitting material, although vacuum evaporationconditions vary with the type of the organic compound to be used in thelight emitting layer, the crystal structure of the molecular accumulatedfilm, the associate structure, and so on, the method is desirablycarried out under such conditions that the boat heating temperature is100° to 350° C., the degree of vacuum is 10⁻⁵ to 10⁻² Pa, the rate ofvacuum evaporation is 0.01 to 50 nm/sec, the substrate temperature is-50° C. to +300° C., and the film thickness is 5 nm to 5 μm.

After formation of the light emitting layer, a thin film of a substancefor negative electrode is formed in a thickness of not more than 1 μm,preferably 50 to 200 nm by a method such as vacuum evaporation orsputtering to provide a negative electrode. In this manner, the desiredEL device is obtained.

In this formation of the EL device, the order can be reversed; that is,the EL device can be produced in the order of negative electrode, lightemitting layer, and positive electrode.

Next, a process for production of an EL device comprising positiveelectrode/hole injection layer/light emitting layer/negative electrodeis explained.

A positive electrode is formed in the same manner as in the above ELdevice, and a thin film of a hole transporting compound is formed on thepositive electrode by a vacuum evaporation method, for example, toprovide a hole injection layer. This vacuum evaporation can be carriedout under the same conditions as in formation of the thin film of thelight emitting material.

Then, on the hole injection layer, a light emitting layer and a negativeelectrode are provided in the same manner as in production of the aboveEL device. In this manner, the desired EL device is obtained.

Also in this formation of the EL device, the order of production can bereversed; that is, the EL device can be produced in the order ofnegative electrode, light emitting layer, hole injection layer, andpositive electrode.

Finally, a process for production of an EL device comprising positiveelectrode/hole injection layer/light emitting layer/electron injectionlayer/negative electrode is explained.

In the same manner as in production of the above EL device, a positiveelectrode, a hole injection layer, and a light emitting layer areprovided in this order. On this light emitting layer, a thin film of anelectron transporting compound is formed by a vacuum evaporation method,for example, to provide an electron injection layer. Then, on theelectron injection layer, a negative electrode is provided in the samemanner as in production of the above EL device. In this manner, thedesired EL device is obtained.

Also in this formation of the EL device, the order of production can bereversed; that is, the EL device can be produced in the order ofnegative electrode, light emitting layer, positive hole injection layer,and positive electrode.

In a case where a DC voltage is applied to the EL device as obtainedabove, when a voltage of 3 to 40 V is applied with the polarity ofpositive electrode as + and the polarity of negative electrode as -,light emission is observed from the side of the transparent ortranslucent electrode. Even if, however, a voltage is applied in thereverse polarity, no current flows and light emission is not observed atall.

In a case where an AC voltage is applied, light emission is observedonly when the positive electrode is + and the negative electrode is -.In this case, the wave form of the AC voltage applied is not critical.

The organic EL device of the present invention provides EL lightemission at a luminance of several hundred cd/m² in the region of bluishpurple to green and at a luminance of at least 1,000 cd/m² in the regionof blue to green, and at the same time, to obtain efficient EL lightemission of more than 0.5 lm/W at a luminance of a practical level (50to 200 cd/m²).

Moreover, the novel aromatic dimethylidyne compounds of the presentinvention are expected to be effectively utilized as various functionalmaterials, utilizing their properties such as electron transportingproperties, luminescence properties, electron injection properties, andthin film properties.

The present invention is described in greater detail with reference tothe following examples.

EXAMPLE 1 (1) Preparation of Arylene Group-Containing PhosphorusCompound

8.0 g of 1,4-bis(chloromethyl)benzene and 13.0 g of trimethyl phosphitewere stirred for 4 hours while heating at a temperature of 150° C. on anoil bath in a stream of argon gas.

Then, excessive trimethyl phosphite and methyl chloride by-produced weredistilled away under reduced pressure. When the residue was allowed tostand for one night, 10.0 g of white crystal was obtained (yield 68%).The melting point was 65°-70° C. The results of a proton nuclearmagnetic resonance ¹ H--NMR) analysis of the white crystal were asfollows:

¹ H--NMR (CDCl₃);

δ=7.0 ppm (s; 4H, benzene ring --H);

δ=3.5 ppm (d; 12H, ester --OCH₃);

δ=3.0 ppm (d; J=16 Hz (³¹ P--¹ H coupling); 4H, P--CH₂).

The above results confirmed that the above product was an arylenegroup-containing phosphorus compound (phosphonate) having the followingformula: ##STR17##

(2) Preparation of Aromatic Dimethylidyne Compound

5.0 g of the phosphate obtained in (1) above and 5.0 g of4,4'-dimethylbenzophenone were dissolved in 100 ml of tetrahydrofuran,and 3.0 g of potassium tert-butoxide was added thereto. The resultingmixture was stirred for 5 hours at room temperature in a stream ofargon, and was allowed to stand overnight.

Then, 100 ml of water was added to the above mixture, and precipitatedcrystals were filtered off. The crystals were washed thoroughly withwater and then with methanol, and recrystallized from benzene to obtain2.0 g of yellowish green crystals (yield 30%). Melting point was215.0°-216.0° C. The results of a ¹ H--NMR analysis of the crystal areas follows:

¹ H--NMR (CDCl₃)

δ=7.0 to 7.2 ppm (m; 16H, p-tolylbenzene ring --H);

δ=6.8 ppm (d; 4H, benzene ring --H, d; 2H, methylidyne --CH═C--);

δ=2.3 ppm (d; 12H, p-tolylmethyl group --CH₃).

By a direct type mass spectrum (MS), a molecular ion peak m/Z=490 of thedesired product was detected.

The results of an elemental analysis (as C₃₈ H₃₄) were as follows. Thevalues in the parentheses indicate theoretical values.

C: 93.10% (93.07%);

H: 6.90% (6.93%);

N: 0.00% (0%);

In an infrared ray (IR) absorption spectral (KBr tablet method)analysis, absorptions due to stretch vibration of C═C were observed at1520 cm⁻¹ and 1620 cm⁻¹.

The above results confirmed that the above product, yellowish greencrystal, was a 1,4-phenylenedimethylidyne derivative having thefollowing formula: ##STR18##

EXAMPLES 2 TO 5

The 1,4-phenylenedimethylidyne derivatives shown in Table 1 wereprepared in the same manner as in Example 1 (2) except that the ketonesshown in Table 1 were used in place of 4,4'-dimethylbenzophenone.

    TABLE 1             IR     Composition Melt-   Absorption    Formula ing   Spectrum      Structural Formula of (molecular Point   (KBr Elemental Analysis (%)     No. Ketone Aromatic Dimethylidyne Compound weight) (°C.) .sup.1     H-NMR (CDCl.sub.3, TMS) Properties tablet) (theoretical value)                Ex-am-ple2      ##STR19##      ##STR20##      C.sub.34 H.sub.26(434.34) 193.0to193.5 δ = 7.2 ppm (s;20H,     terminal aromatic ring H)δ = 6.8 ppm (d;4H, central benzenering     H) (d;2H, methylidyne CHC) YellowishGreenPowder ν.sub.c=c1510     cm.sup.-11620 cm.sup.-1 C 94.32 (94.01)H  6.04 ( 5.99)N  0.00 (   0)     a     Ex-m-ple3      ##STR21##      ##STR22##      C.sub.36 H.sub.30(462.36) 117.0to118.5 δ = 7.0 to 7.4 ppm(m;18H,     terminal aromaticring H)δ = 6.85 ppm (d;4H, central benzenering     H)(d;2H, methylidyne CHC)δ 2.4 ppm (d;6H, p-tolylmethyl CH.sub.3)     YellowishGreenPowder ν.sub.c=c1520 cm.sup.-1 1610 cm.sup.-1 C 93.30     (93.51)H  6.23 ( 6.49)N  0.00 (   0)      Ex-am-ple4     ##STR23##      ##STR24##      C.sub.34 H.sub.38(446.34) 175.0to177.0 δ = 6.8 to 7.2 ppm(m;18H,     terminal aromaticring H)δ = 6.4 ppm (s;4H, central benzenering     H)δ = 6.1 ppm (s;2H, methylidyne CHC)δ = 1 to 2 ppm(m;22H,     cyclohexyl H) WhitePowder ν.sub.c=c1520 cm.sup.-11620 cm.sup.-1 C     91.68 (91.49)H  8.47 (  8.51)N  0.00 (   0)      Ex-am-ple5     ##STR25##      ##STR26##      C.sub.36 H.sub.30 O.sub.2(494.36) 162.0to164.0 δ = 6.8 to 7.3     ppm(m;20H, terminal aromaticring H)δ = 6.8 ppm (m;4H, central     benzenering H)(m;2H, methylidyne CHC)δ = 3.8 ppm (s;6H, methoxy     group OCH.sub.3) YellowishGreenPowder ν.sub.c=c1520 cm.sup.-11610     cm.sup.-1 C 87.24 (87.46)H  6.24 ( 6.07)N  0.00 (       0)

EXAMPLE 6 (1) Preparation of Arylene Group-Containing PhosphorusCompound

25 g of 2,5-bis(chloromethyl)xylene and 45 g of triethyl phosphite werestirred while heating at 150° C. for 7 hours on an oil bath in a streamof argon.

Then, excessive triethyl phosphite and ethyl chloride by-produced weredistilled away under reduced pressure. After allowing to standovernight, 50 g of white crystal (quantitatively) was obtained. Meltingpoint: 59.0°-60.5° C. The results of a ¹ H--NMR analysis were asfollows.

¹ H--NMR (CDCl₃);

δ=6.9 ppm (s; 2H, central xylene ring --H);

δ=3.9 ppm (q; 8H, ethoxy group methylene --CH₂);

δ=3.1 ppm (d; 4H, J=20 Hz (³¹ P--¹ H coupling) P--CH₂);

δ=2.2 ppm (s; 6H, xylene ring --CH₃);

δ=1.1 ppm (t; 12H, ethoxy group methyl --CH₃).

The above results confirmed that the above product was an arylenegroup-containing phosphorus compound (phosphonate) having the followingformula: ##STR27##

(2) Preparation of Aromatic Dimethylidyne Compound

5.3 g of the phosphonate obtained in (1) above and 5.2 g of2-benzoylbiphenyl were dissolved in 100 ml of tetrahydrofuran, and 12.3g of a hexane solution containing n-butyllithium (concentration 15%) wasadded. The resulting mixture was stirred at room temperature for 6 hoursin a stream of argon, and was allowed to stand overnight.

To the mixture thus obtained was added 300 ml of methanol, andprecipitated crystals were filtered off. The filtered product wasthoroughly washed three times with 100 ml of water and then three timeswith 100 ml of methanol to obtain 5.5 g of light yellow powder (yield44%). The melting point was 187°-188° C. The results of a ¹ H--NMRanalysis of the powder were as follows:

¹ H--NMR (CDCl₃);

δ=7.7 to 7.0 ppm (m; 30H, aromatic ring);

δ=6.7 ppm (s; 2H, methylidyne --CH═C--);

δ=2.0 ppm (s; 6H, xylene ring --CH₃).

The results of elemental analysis (Composition Formula C₄₈ H₃₈) were asfollows. The values in the parentheses were theoretical values.

C: 93.79% (93.82%);

H: 6.06% (6.18%);

N: 0.00% (0%).

An infrared ray (IR) absorption spectrum (KBr method) was as follows:

    ν.sub.c═c 1520, 1620 cm.sup.-1.

The above results confirmed that the above product, light yellow powderwas a 2,5-xylenedimethylidyne derivative having the following formula:##STR28##

EXAMPLE 7 TO 12

The 2,5-xylenedimethylidyne derivatives shown in Table 2 were preparedin the same manner as in Example 6 (2) except that the ketones were usedin place of 2-benzoylbiphenyl.

    TABLE 2         Compo-         sition    IR    Formula    Absorption    (mole-     Melting   Spectrum   Structural Formula of cular Point   (KBr Elemental     Analysis (%) No. Ketone Aromatic Dimethylidyne Compound weight) (°     C.) .sup.1 H-NMR (CDCl.sub.3, TMS) Properties tablet) (theoretical     value)           Ex-am-ple7      ##STR29##      ##STR30##      C.sub.34 H.sub.26(434.34) 242to243.5 δ = 6.9 to 7.1 ppm(m;16H,     terminal tolylgroup benzene ring H)δ = 6.7 ppm (s;2H, central     xylenering H)δ = 6.5 ppm (s;2H, methylidyne CCH)δ = 2.3 ppm     (s;12H, terminal tolylgroup CH.sub.3)δ = 2.0 ppm (s;6H, central     xylenering CH.sub.3) LightYellowPowder ν.sub.c=c1510 cm.sup.-11620     cm.sup.-1 C 92.60 (92.67)H  7.23 ( 7.33)N  0.00 (   0)  Ex-am-ple8      ##STR31##      ##STR32##      C.sub.44 H.sub.34(562.44) 199to205 δ = 7.0 to 7.8 ppm(m;24H,     aromatic ring)δ = 7.0 ppm (s;2H, central xylenering H)δ =     6.6 ppm (s;2H, methylidyne CCH)δ =      2.0 ppm (s;6H, central xylenering CH.sub.3) LightYellowPowder ν.sub.c     =c1510 cm.sup.-11620 cm.sup.-1 C 93.87 (93.95)H  5.82 ( 6.05)N   0.00 (      0)      Ex-am-ple9     ##STR33##      ##STR34##      C.sub.38 H.sub.46 O.sub.2(534.48) 172to174 δ = 6.2 to 7.2     ppm(m;12H, terminal benzene ring,xylene ring H, and methylidyneCCH).delta     . = 3.8 ppm (s;6H, methoxy group OCH.sub.3)δ = 1.9 ppm (s;6H,     central xylene ringCH.sub.3)δ = 0.8 to 0.2 ppm(b;22H, cyclohexane     ring) LightYellowPowder ν.sub.c=c1520 cm.sup.-11620 cm.sup.-1 C 85.06     (85.39)H  8.82 ( 8.61)N  0.00 (   0)      Ex-am-ple10     ##STR35##      ##STR36##      C.sub.34 H.sub.28 N.sub.2(464.34) 192to192.5 δ = 7.0 to 8.5     ppm(m;20H, terminal benzenering H, central xylene ring H,and pyridine     ring)δ = 6.5 ppm (s;2H, methylidyne  CCH)δ = 2.0 ppm (s;6H,     central ring CH.sub.3) YellowPowder ν.sub.c=c1510 cm.sup.-11610     cm.sup.-1 C 87.79 (87.94)H  5.90 ( 6.03)N  0.00 (   0)  Ex-am-ple11      ##STR37##      ##STR38##      C.sub.36      H.sub.42(474.36) 177.5to179     ##STR39##      WhitePowder ν.sub.c=c1520 cm.sup.-11620 cm.sup.-1 C 91.02 (91.15)H     8.89 ( 8.85)N  0.00 (   0)      CH.sub.3)      δ = 1.0 to 2.0 ppm         (b;22H, cyclohexane ring)      Ex-am-ple12     ##STR40##      ##STR41##      C.sub.42 H.sub.54(558.89) 166to167 δ = 6.5 to 6.9 ppm(m;12H,     aromatic ring H)δ = 2.8 ppm (m;2H, isopropyl group CH)δ =     1.8 ppm (s;6H, central xylene ringCH.sub.3)δ = 1.2 ppm (d;12H,     isopropyl groupCH.sub.3)δ = 1.0 to 2.0 ppm(b;22H, cyclohexane     ring) WhitePowder ν.sub.c=c1520 cm.sup.-11620 cm.sup.-1 C 90.15     (90.26)H  9.69 ( 9.74)N  0.00 (     *Value of mass spectrum, m/Z = 534     **Value of mass spectrum, m/Z = 464     ***Value of mass spectrum, m/Z = 558.     iPr indicates an isopropyl group.

EXAMPLE 13 (1) Preparation of Phosphorus Compound

25.1 g of (1-bromoethyl)benzene and 24.7 g of triethyl phosphite wereheated with stirring at 150° C. for 7 hours on an oil bath in a streamof argon. Then, excessive triethyl phosphite and bromoethyl by-producedwere distilled away under reduced pressure to obtain 22.3 g of atransparent solution. The results of a ¹ H--NMR analysis were asfollows:

δ=7.2 ppm (s; 5H, benzene ring --H)

δ=3.9 ppm (q; 4H, ethoxy group --OCH₂ --);

δ2.9 to 3.5 ppm (m; ¹ H, ═CH--);

δ1.0 to 2.0 ppm (m; 9H, methyl of ethoxy and --CH₃).

The above results confirmed that the above product was a phosphoruscompound (phosphonate) having the following formula: ##STR42##

(2) Preparation of Aromatic Dimethylidyne Compound

9.7 g of the phosphonate obtained in (1) above and 3.0 g ofterephthalaldehyde were dissolved in 100 ml of tetrahydrofuran, and 3.0g of a hexane solution containing n-butyl lithium (concentration 15%)was added thereto. The resulting mixture was stirred for 5 hours at roomtemperature in a stream of argon, and then was allowed to standovernight.

To the mixture above obtained, 100 ml of methanol was added, andprecipitated crystals were filtered off. The filtered product wasthoroughly washed three times with 100 ml of water and then three timeswith 100 ml of methanol to obtain 1.3 g of white flaky crystals (yield20%). Melting point was 179°-180° C. The results of a ¹ H--NMR analysisof the crystal were as follows.

¹ H--NMR (CDCl₃);

δ=7.2 to 7.5 ppm (m; 14H, benzene ring --H);

δ=6.8 ppm (s; 2H, methylidyne --CH═C--);

δ=2.3 ppm (s; 6H, methyl group).

The results of elemental analysis (as composition formula, C₂₄ H₂₂) wereas follows. The values in the parentheses are theoretical values.

C: 92.84% (92.91%);

H: 7.23% (7.09%);

N: 0.00% (0%);

In a mass spectrum, a molecular ion peak m/Z=310 of the desired productwas detected.

The above results confirmed that the above product of white flakycrystal was a 1,4-phenylenedimethylidyne derivative having the followingformula: ##STR43##

EXAMPLE 14

A 2,5-xylenedimethylidyne derivative having the formula: ##STR44## wasprepared in the same manner as in Example 13 (2) except that2,5-xylenedicarboxyaldehyde was used in place of terephthalaldehyde.

Analytical results were as follows:

Melting point, 137.0°-137.8° C.

¹ H--NMR (CDCl₃);

δ=6.8 to 7.5 ppm (m; 14H, benzene ring --H, central xylene ring --H,methylidyne --CH═C--);

δ=2.3 ppm (s: 6H, terminal methyl group --CH₃);

δ=2.1 ppm (s; 6H, central xylene ring --CH₃);

Shape: white powder.

Elemental Analysis (as composition formula C₂₆ H₂₆). The values in theparentheses are theoretical values.

C: 92.26% (92.31%);

H: 7.50% (7.69%);

N: 0.00% (0%).

EXAMPLE 15 (1) Preparation of Arylene Group-Containing PhosphorusCompound

9.0 g of 4,4'-bis(bromomethyl)biphenyl and 11 g of triethyl phosphitewere heated with stirring at 140° C. for 6 hours on an oil bath in astream of argon.

Then, excessive triethyl phosphite and ethyl bromide by-produced weredistilled away under reduced pressure. After allowing to standovernight, 9.5 g of white crystals were obtained yield 80%). The meltingpoint was 97.0°-100.0° C. The results of a ¹ H--NMR analysis were asfollows:

¹ H--NMR (CDCl₃):

δ=7.0 to 7.6 ppm (m; 8H, biphenylene ring --H);

δ=4.0 ppm (q; 8H, ethoxy group methylene --CH₂);

δ=3.1 ppm (d; 4H, J=20 Hz (³¹ P--¹ H coupling) P--CH₂);

δ=1.3 ppm (t; 12H, ethoxy group methyl --CH₃).

The above results confirmed that the above product was an arylenegroup-containing phosphorus compound (phosphonate) having the followingformula: ##STR45##

(2) Preparation of Aromatic Dimethylidyne Compound

4.0 g of the phosphonate obtained in (1) above and 5.0 g of cyclohexylphenyl ketone were dissolved in 60 ml of dimethyl sulfoxide, 2.0 g ofpotassium tert-butoxide was added, and the resulting mixture was stirredunder reflux in a stream of argon and then was allowed to standovernight.

After removal by distillation of the solvent from the above mixture, 200ml of methanol was added, and precipitated crystals were filtered off.The filtered product was thoroughly washed three times with 100 ml ofwater and then three times with 100 ml of methanol, and thenrecrystallized from benzene to obtain 1.0 g of light yellow powder(yield 22%). The melting point was 153°-155° C. The results of a ¹H--NMR analysis of the powder were as follows:

¹ H--NMR (CDCl₃):

δ=6.3 to 7.5 ppm (b; 18H, aromatic ring and methylidyne --CH═C--);

δ=1.0 to 2.0 ppm (b; 22H, cyclohexane ring).

The results of elemental analysis (as composition formula C₄₀ H₄₂) wereas shown below. The values in the parentheses are theoretical values.

C: 91.74% (91.90%);

H: 8.25% (8.10%);

N: 0.00% (0%).

The results of an infrared ray (IR) absorption spectrum (KBr tabletmethod) were as follows:

    ν.sub.c═c 1250, 1610 cm.sup.-1.

In a mass spectrum, a molecular ion peak m/Z=522 of the desired productwas detected.

The above results confirmed that the above product was a4,4'-biphenylenedimethylidyne derivative having the following formula:##STR46##

EXAMPLE 16

A 4,4'-biphenylenedimethylidyne derivative having the following formula:##STR47## was prepared in the same manner as in Example 15 (2) except

that 4,4'-dimethylbenzophenone was used in place of cyclohexyl phenylketone, and tetrahydrofuran, in place of dimethyl sulfoxide.

The analytical results were as shown below.

Melting point: 228°-230° C..

¹ H--NMR (CDCl₃):

δ=6.7 to 7.3 ppm (m; 26H, aromatic ring --H and methylidyne --CH═C--):

δ=2.4 ppm (s; 12H, p-tolylmethyl group --CH₃).

Shape: light yellow powder.

Molecular ion peak of mass spectrum: m/Z=566.

Elemental analysis: as shown below (as composition formula, C₄₄ H₃₈).The values in the parentheses are theoretical values.

C: 93.10% (93.24%);

H: 7.04% (6.76%);

N: 0.00% (0%);

EXAMPLE 17 (1) Preparation of Arylene Group-Containing PhosphorusCompound

24.3 g of 2,6-bis(bromomethyl)naphthalene and 50 g of triethyl phosphitewere heated with stirring at 120° C. for 7 hours on an oil bath in astream of argon.

Then, excessive triethyl phosphite and ethyl bromide by-produced weredistilled away under reduced pressure. After allowing to standovernight, 32.5 g of light yellow crystals were obtained (yield,quantitatively). The melting point was 144.5°-146.0° C. The results of a¹ H--NMR analysis were as shown below.

¹ H--NMR (CDCl₃):

δ=7.2 to 7.8 ppm (m; 6H, naphthylene ring --H);

δ=4.0 ppm (q; 8H, ethoxy group methylene --CH₂);

δ=3.3 ppm (d; 4H, J=20 Hz (31P--¹ H coupling); P--CH₂);

δ=1.2 ppm (t; 12H, ethoxy group methyl --CH₃).

The above results confirmed that the above product was an arylenegroup-containing phosphorus compound (phosphonate) having the followingformula: ##STR48##

(2) Preparation of Aromatic Dimethylidyne Compound

5.0 g of the phosphonate obtained in (1) above and 5.0 g of cyclohexylphenyl ketone were dissolved in 100 ml of tetrahydrofuran, 2.5 g ofpotassium tert-butoxide was added thereto, and the resulting mixture wasstirred under reflux in a stream of argon and then was allowed to standovernight.

After removal by distillation of the solvent from the mixture aboveobtained, 100 ml of methanol was added, and precipitated crystals werefiltered off. The filtered product was thoroughly washed twice with 100ml of water and then twice with 100 ml of methanol, and thenrecrystallized from benzene to obtain 1.0 g of light yellow powder(yield 20%). The melting point was 215°-216° C. The results of a ¹H--NMR analysis of the powder were as shown below.

¹ H--NMR (CDCl₃):

δ=6.2 to 7.2 ppm (m; 18H, aromatic ring and naphthalene ring --H, andmethylidyne --CH═C--);

δ=1.0 to 2.0 ppm (b; 22H, cyclohexane ring).

The results of elemental analysis (as composition formula C₃₈ H₄₀) wereas shown below. The values in the parentheses are theoretical values.

C: 91.63% (91.88%);

H: 8.20% (8.12%);

N: 0.00% (0%).

The above results confirmed that the above product, light yellow powderwas a 2,6-naphthylenedimethylidyne derivative having the followingformula: ##STR49##

EXAMPLE 18

A 2,6-naphthylenedimethylidyne derivative having the following formula:##STR50## was prepared in the same manner as in Example 17 (2) exceptthat 4,4'-dimethylbenzophenone was used in place of cyclohexyl phenylketone, and n-butyl lithium, in place of potassium tert-butoxide.

The analytical results are shown below.

Melting point: 269°-271° C.

¹ H--NMR (CDCl₃);

δ=6.7 to 7.2 ppm (m; 24H, aromatic ring --H and methylidyne --CH═C--);

δ=2.4 ppm (s; 12H, p-tolylmethyl group --CH₃).

Shape: yellow powder.

Elemental analysis: as shown below (as composition formula C₄₂ H₃₆). Thevalues in the parentheses are theoretical values.

C: 93.03% (93.29%);

H: 6.81% (6.71%);

N: 0.00% (0%).

EXAMPLE 19 (1) Preparation of Arylene Group-Containing PhosphorusCompound

10 g of 9,10-bis(chloromethyl)anthracene and 35 g of triethyl phosphitewere heated with stirring at 130° C. for 6 hours on an oil bath in astream of argon.

Then, excessive triethyl phosphite and ethyl chloride by-produced weredistilled away under reduced pressure. After allowing to standovernight, light green crystals were obtained, and the crystals werethen recrystallized from benzene-hexane to obtain 16 g of light yellowflaky crystals (yield 92%).

The analytical results are shown below.

Melting point: 160°-161.5° C.

¹ H--NMR (CDCl₃):

δ=7.3 to 8.4 ppm (m; 8H, anthracene ring --H);

δ=4.1 ppm (d; 4H, J=20 Hz (31P--¹ H coupling) P--CH₂);

δ=3.7 ppm (q; 8H; ethoxy group methylene --CH₂);

δ=1.0 ppm (t; 12H, ethoxy group methyl --CH₃).

The above results confirmed that the above product was an arylenegroup-containing phosphorus compound (phosphonate) having the followingformula: ##STR51##

(2) Preparation of Aromatic Dimethylidyne Compound

3.0 g of the phosphonate obtained in (1) above and 2.5 g of4,4'-dimethylbenzophenone were dissolved in 100 ml of tetrahydrofuran, 5g of a hexane solution containing n-butyl lithium (concentration 15%)was added thereto, and the resulting mixture was stirred for 4 hours atroom temperature in a stream of argon and then was allowed to standovernight.

To the mixture obtained above, 100 ml of methanol was added, andprecipitated crystals were filtered off. The filtered product wasthoroughly washed three times with 100 ml of water and then three timeswith 100 ml of methanol, and then recrystallized from toluene to obtain0.7 g of yellowish orange powder (yield 19%).

The analytical results are shown below.

Melting point: 297°-298° C.

¹ H--NMR (CDCl₃):

δ=6.5 to 7.5 ppm (m; 26H, aromatic ring --H, anthracene --H, andmethylidyne --CH═C--);

δ=2.2 ppm (d; 12H, p-tolylmethyl group --CH₃).

Elemental analysis: As shown below as composition formula C₄₆ H₃₈. Thevalues in the parentheses indicates theoretical values.

C: 93.42% (93.52%);

H: 6.53% (6.48%);

N: 0.00% (0%).

In a mass spectrum, a molecular ion peak m/Z=590 of the desired productwas detected.

The above results confirmed that the above product, yellowish orangepowder, was a 9,10-anthracenediyldimethylidyne derivative having thefollowing formula: ##STR52##

EXAMPLE 20

A member comprising a 25 mm×75 mm×1.1 mm glass substrate and a 100 nmthick film of ITO provided on the glass substrate by a vacuumevaporation method (produced by HOYA Co., Ltd.) was used as atransparent substrate.

This transparent substrate was attached to a substrate holder of acommercially available evaporation system (manufactured by ULVAC Co.,Ltd.). In an electrically heated boat made of molybdenum, 200 mg ofN,N'-diphenyl-N,N'-bis-(3-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine(TPDA) was placed, and in the other boat of molybdenum, 200 mg of a1,4-phenylenedimethylidyne derivative,1,4-bis(2,2-di-p-tolylvinyl)benzene (DTVB), was placed. The pressure ofthe vacuum chamber was decreased to 1×10⁻⁴ Pa.

The boat in which TPDA was placed was heated to 215° to 220° C., andTPDA was vapor deposited (vacuum deposited) on the transparent substrateat a deposition speed of 0.1 to 0.3 nm/sec to form a hole injectionlayer with a film thickness of 60 nm. The temperature of the substrateat this time was room temperature.

Then, without taking the substrate out of the vacuum chamber, DTVB wasvacuum deposited from the other boat in a 80 nm laminate film form as alight emitting layer. In connection with vacuum deposition conditions,the temperature of the boat was 237° to 238° C., the vacuum depositionspeed was 0.1 to 0.3 nm/sec, and the substrate temperature was roomtemperature.

The substrate was taken out of the vacuum chamber. A stainless steelmask was placed on the above light emitting layer, and was then attachedto the substrate holder.

Then, 1 g of magnesium ribbon was placed on an electrically heated boatmade of molybdenum, and in the other electrically heated boat made ofmolybdenum, 500 mg of indium was placed. The pressure of the vacuumchamber was decreased 2×10⁴ Pa. Then, the indium was vacuum deposited ata vacuum deposition speed of 0.03 to 0.08 nm/sec, and at the same time,magnesium in the other boat was vacuum deposited at a vacuum depositionspeed of 1.7 to 2.8 nm/sec. The temperature of the boat containingindium was 800° C., and the temperature of the boat containing magnesiumwas 500° C.

Under the above conditions, a magnesium-indium mixed metal electrode wasvacuum deposited in a thickness of 150 nm on the light emitting layer asan opposite electrode to thereby produce a device.

Upon application of a DC voltage of 20 V onto the above device with theITO electrode as a positive electrode and the magnesium-indium mixedmetal electrode as a negative electrode, a current of about 100 mA/cm²flew and the emitted light was blue green in the chromaticitycoqrdinates. The wavelength of the peak as determined by spectrometerwas 486 nm. The maximum luminance was 1,000 cd/m².

EXAMPLE 21

A member comprising a 25 mm×75 mm×1.1 mm glass substrate and a 100 nmthick ITO film provided by a vacuum deposition method (manufactured byHOYA Co., Ltd.) was used as a transparent substrate.

This transparent substrate was attached to a substrate holder of acommercially available vacuum deposition system (manufactured by ULVACCo., Ltd.). In an electrically heated boat made of molybdenum, 200 mg ofTPDA was placed, and in the other boat, 200 mg of the1,4-phenylenedimethylidyne derivative obtained in Example 2,1,4-bis(2,2-di-phenylvinyl)benzene (DPVB), was placed. The pressure ofthe vacuum chamber was decreased to 1×10⁻⁴ Pa.

Then, the above boat in which TPDA was placed was heated to 215° to 220°C., and TPDA was vacuum deposited at a vacuum deposition speed of 0.1 to0.3 nm/sec on the transparent substrate to thereby produce a holeinjection layer with a film thickness of 60 nm. At this time, thesubstrate was at room temperature.

Then, without taking the substrate out of the vacuum chamber, on thepositive hole injection layer, DPVB was vacuum deposited from the otherboat in a thickness of 80 nm as a light emitting layer. In connectionwith the vacuum deposition conditions, the boat temperature was 152° to153° C., the vacuum deposition speed was 0.1 to 0.3 nm/sec, and thesubstrate temperature was room temperature.

The substrate was taken out of the vacuum chamber. A stainless steelmask was placed on the above light emitting layer and then attached tothe substrate holder.

In an electrically heated boat made of molybdenum, 1 g of magnesiumribbon was placed, and in the other electrically heated boat made ofmolybdenum, 500 mg of indium was placed.

The pressure of the vacuum chamber was decreased to 2×10⁻⁴ Pa. Then,indium was vacuum deposited at a vacuum deposition speed of 0.03 to 0.08nm/sec, and from the other boat, magnesium was vacuum deposited at avacuum deposition speed of 1.7 to 2.8 nm/sec. The temperature of theboat containing indium was 800° C., and the temperature of the boatcontaining magnesium was 500° C.

Under the above conditions, a magnesium-indium mixed metal electrode wasvacuum deposited on the light emitting layer as the opposite electrodeto thereby produce a device.

Upon application of a DC voltage of 10 V onto the device with the ITOelectrode as a positive electrode and the magnesium-indium mixed metalelectrode as a negative electrode, a current of about 1.1 mA/cm² flew,and a luminance of 50 cd/m² was obtained. At this time, luminousefficiency was 1.2 lm/W. Furthermore, upon application of a DC voltageof 17.5 V, a current of about 75 mA/cm² flew, and the emitted light wasgreenish blue in the chromaticity coordinates. The wavelength of thepeak was 483 nm, and the maximum luminance was 1,000 cd/m².

EXAMPLE 22

A member comprising a 25 mm×75 mm×1.1 mm glass substrate and a 100 nmthick ITO film provided thereon by a vacuum deposition method(manufactured by HOYA Co., Ltd.) was used as a transparent substrate.

This transparent substrate was attached to a substrate holder of acommercially available vacuum deposition system (manufactured by ULVACCo., Ltd.). In an electrically heated boat made of molybdenum, 200 mg ofTPDA was placed, and in the other boat made of molybdenum, 200 mg of the1,4-phenylenedimethylidyne derivative obtained in Example 3,1,4-bis(2-phenyl-2-p-tolyl)benzene (PTVB) was placed. The pressure ofthe vacuum chamber was decreased to 1×10⁻⁴ Pa.

The boat containing TPDA was heated to 215° to 220° C., and TPDA wasvacuum deposited on the transparent substrate at a vacuum depositionspeed of 0.1 to 0.3 nm/sec to thereby produce a hole injection layerwith a film thickness of 60 nm. At this time, the substrate was at roomtemperature.

Without taking the substrate out of the vacuum chamber, PTVB was vacuumdeposited on the hole injection layer from the other boat in a thicknessof 80 nm as a light emitting layer. In connection with vacuum depositionconditions, the boat temperature was about 200° C., the vacuumdeposition speed was 0.2 to 0.4 nm/sec, and the substrate temperaturewas room temperature. The substrate was taken out of the vacuum chamber,and a stainless steel mask was placed on the above light emitting layerand again attached to the substrate holder.

In an electrically heated boat made of molybdenum, 1 g of magnesiumribbon was placed, and in the other electrically heated boat made ofmolybdenum, 500 mg of indium was placed.

The pressure of the vacuum chamber was decreased to 2×10⁻⁴ Pa. Then,indium was vacuum deposited at a speed of 0.03 to 0.08 nm/sec, and atthe same time, from the other boat, magnesium was vacuum deposited at aspeed of 1.7 to 2.8 nm/sec. The temperature of the boat containingindium was 800° C., and the temperature of the boat containing magnesiumwas 500° C.

Under the above conditions, a magnesium-indium mixed metal electrode wasvacuum deposit in a laminated form in a thickness of 150 nm on the lightemitting layer to thereby produce a device.

Upon application of a DC voltage of 20 V onto the device above obtained,with an ITO electrode as a positive electrode and the magnesium-indiummixed metal electrode as a negative electrode, a current of about 100mA/cm² flew, and the emitted light was greenish blue in the chromaticitycoordinates. The wavelength of the peak as determined by spectralmeasurement was 486 nm, and the maximum luminance was 700 cd/m².

EXAMPLE 23

A member comprising a 25 mm×75 mm×1.1 mm glass substrate and a 100 nmthick ITO film provided thereon by a vacuum deposition method(manufactured by HOYA Co., Ltd.) was used as a transparent substrate.

This transparent substrate was attached to a substrate holder of acommercially available vacuum deposition system (produced by ULVAC Co.,Ltd.). Then, 200 mg of TPDA was placed in an electrically heated boatmade of molybdenum, and in the other boat made of molybdenum, 200 mg ofthe 1,4-phenylenedimethylidyne derivative obtained in Example 4,1,4-bis(2-phenyl-2-cyclohexyl vinyl)benzene (PCVB), was placed. Thepressure of the vacuum chamber was decreased to 1×10⁻⁴ Pa.

Then, the above boat containing TPDA was heated to 215° to 220° C., andvacuum deposited on the transparent substrate at a vacuum depositionspeed of 0.1 to 0.3 nm/sec to form a 60 nm thick hole injection layer.At this time, the substrate temperature was room temperature.

Without taking the substrate out of the vacuum chamber, from the otherboat, PCVB was vacuum deposited on the hole injection layer in alaminated form in a thickness of 80 nm. In connection with vacuumdeposition conditions, the boat temperature was 185° to 190° C., thevacuum deposition temperature was 0.1 to 0.3 nm, and the substratetemperature was room temperature.

The substrate was taken out of the vacuum chamber. A stainless steelmask was placed on the above light emitting layer and again attached tothe substrate holder.

In an electrically heated boat made of molybdenum, 1 g of magnesiumribbon was placed, and in the other electrically heated boat made ofmolybdenum, 500 mg of indium was placed.

After the pressure of the vacuum chamber was decreased to 2×10⁻⁴ Pa,indium was vacuum deposited at a vacuum deposition speed of 0.03 to 0.08nm/sec, and from the other boat, magnesium was vacuum deposited at avacuum deposition speed of 1.7 to 2.8 nm/sec. The temperature of theboat containing indium was 800° C., and the temperature of the boatcontaining magnesium was 500° C.

Under the above conditions, a magnesium-indium mixed metal electrode wasvacuum deposited on the light emitting layer in a laminated form in athickness of 150 nm to form the opposite electrode, thereby producing adevice.

Upon application of a DC voltage of 20 V onto the device above obtained,with the ITO electrode as a positive electrode and the magnesium-indiummixed metal electrode as a negative electrode, a current of about 3.5mA/cm² flew, and bluish purple light was emitted. The wavelength of thepeak was 425 nm as determined by spectral measurement. The luminance was50 cd/m², and sufficient light emission was confirmed in a light place.

EXAMPLE 24

A member comprising a 25 mm×75 mm×1.1 mm glass substrate and a 100 nmthick ITO film provided thereon by a vacuum deposition method(manufactured by HOYA Co., Ltd.) was used as a transparent substrate.

This transparent substrate was attached to a substrate holder of acommercially available vacuum deposition system (produced by ULVAC Co.,Ltd.). Then, 200 mg of TPDA was placed in an electrically heated boatmade of molybdenum, and in the other boat made of molybdenum, 200 mg ofthe 1,4-bis [2-(p-methoxyphenyl)-2-phenylvinyl]benzene (MEPVB) obtainedin Example 5 was placed. The pressure of the vacuum chamber wasdecreased to 1×10⁻⁴ Pa.

Then the above boat containing TPDA was heated to 215° to 220° C. andvacuum deposited on the transparent substrate at a vacuum depositionspeed of 0.1 to 0.3 nm/sec to form a 60 nm thick hole injection layer.At this time, the substrate temperature was room temperature.

Without taking the substrate out of the vacuum chamber, from the otherboat, MEPVB was vacuum deposited on the hole injection layer in athickness of 80 nm in a laminated form as a light emitting layer. Inconnection with vacuum conditions, the boat temperature was 107° C., thevacuum deposition speed was 0.4 to 0.6 nm/sec, and the substratetemperature was room temperature.

The substrate was taken out of the vacuum chamber. A stainless steelmask was placed on the above light emitting layer and again attached tothe substrate holder.

Then, in an electrically heated boat made of molybdenum, 1 g ofmagnesium ribbon was placed, and in the other electrically heated boatmade of molybdenum, 500 mg of indium was placed.

After the pressure of the vacuum chamber was decreased to 2×10⁻⁴ Pa,indium was vacuum deposited at a vacuum deposition speed of 0.03 to 0.08nm/sec, and from the other boat, magnesium was vacuum deposited at avacuum deposition speed of 1.7 to 2.8 nm/sec. The temperature of theboat containing indium was 800° C., and the temperature of the boatcontaining magnesium was 500° C. Under the above conditions, amagnesium-indium mixed metal electrode was vacuum deposited on the lightemitting layer in a thickness of 150 nm in a laminated form to form theopposite electrode, thereby producing a device.

Upon application of a DC voltage of 12 V onto the device above obtained,with the ITO electrode as a positive electrode and the magnesium-indiummixed metal electrode as a negative electrode, a current of about 160mA/cm² flew, and the emitted light was blue green in the chromaticitycoordinates, and the luminance was 700 cd/m².

EXAMPLE 25

A member comprising a 25 mm×75 mm×1.1 mm glass substrate and a 100 nmthick ITO film provided thereon by vacuum deposition method(manufactured by HOYA Co., Ltd.) was used as a transparent substrate.

This transparent substrate was attached to a substrate holder of acommercially available vacuum deposition system (produced by ULVAC Co.,Ltd.). Then, 200 mg of TPDA was placed in an electrically heated boatmade of molybdenum, and in the other boat made of molybdenum, 200 mg ofthe 2,5-xylenedimethylidyne derivative obtained in Example 6,2,5-bis(2-phenyl-2-biphenylvinyl)xylene (BPVX) was placed. The pressureof the vacuum chamber was decreased to 1×10⁻⁴ Pa.

Then, the above boat containing TPDA was heated to 215° to 220° C. andvacuum deposited at a vacuum deposition speed of 0.1 to 0.3 nm/sec onthe transparent substrate to form a 60 nm thick hole injection layer. Atthis time, the substrate temperature was room temperature.

Without taking the substrate out of the vacuum chamber, from the otherboat, BPVX was vacuum deposited on the hole injection layer in athickness of 80 nm in a laminated form as a light emittting layer. Inconnection vacuum deposition conditions, the boat temperature was 184°C., the vacuum deposition speed was 0.2 to 0.4 nm/sec, and the substratetemperature was room temperature.

The substrate was taken out of the vacuum chamber. A stainless steelmask was placed on the above light emitting layer and again attached tothe substrate holder.

Then, 1 g of magnesium ribbon was placed in an electrically heated boatmade of molybdenum, and in the other electrically heated boat made ofmolybdenum, 500 mg of indium was placed.

Then the pressure of the vacuum chamber was decreased to 2×10⁻⁴ Pa.Then, indium was vacuum deposited at a vacuum deposition of speed of0.03 to 0.08 nm/sec, and from the other boat, magnesium was vacuumdeposited at a vacuum deposition speed of 1.7 to 2.8 nm/sec. Thetemperature of the boat containing indium was 800° C., and thetemperature of the boat containing magnesium was 500° C. Under the aboveconditions, a magnesium-indium mixed metal electrode was vacuumdeposited on the light emitting layer in a thickness of 150 nm in alaminated form to form the opposite electrode, thereby producing adevice.

Upon application of a DC voltage of 20 V onto the device above obtained,with the ITO electrode as a positive electrode and the magnesium-indiummixed metal electrode as a negative electrode, a current of about 170mA/cm² flew, and light emission in bluish green in the chromaticitycoordinates was obtained. The wavelength of the peak was 499 nm asdetermined by spectral measurement, and the luminance was more than1,000 cd/m².

EXAMPLE 26

A member comprising a 25 mm×75 mm×1.1 mm glass substrate and a 100 nmthick ITO layer provided thereon by a vacuum deposition method(manufactured by HOYA Co., Ltd.) was used as a transparent substrate.

This transparent substrate was subjected to UV ozone cleaning for 2minutes by the use of a UV ozone treating apparatus (manufactured byNippon Battery Co., Ltd.).

The substrate was attached to a substrate holder of a commerciallyavailable vacuum deposition system (produced by ULVAC Co., Ltd.). Then,200 mg of TPDA was placed in an electrically heated boat made ofmolybdenum, and in the other boat made of molybdenum, 200 mg of the2,5-xylenedimethylidyne derivative obtained in Example 7,2,5-bis(2,2-di-p-tolyvinyl)xylene (DTVX), was placed. The pressure ofthe vacuum chamber was decreased to 1×10⁻⁴ Pa.

The above boat containing TPDA was heated to 215° to 220° C. and vacuumdeposited on the transparent substrate at a vacuum deposition speed of0.1 to 0.3 nm/sec to form a 60 nm thick hole injection layer. At thistime, the substrate temperature was room temperature.

Without taking the substrate out of the vacuum chamber, from the otherboat, DTVX was vacuum deposited on the hole injection layer in athickness of 80 nm in a laminated form as a light emitting layer. Inconnection with vacuum deposition conditions, the boat temperature was215° C., the vacuum deposition speed was 0.2 to 0.4 nm/sec, and thesubstrate temperature was room temperature.

The substrate was taken out of the vacuum chamber. A stainless steelmask was placed on the above light emitting layer and again attached tothe substrate holder.

In an electrically heated boat made of molybdenum, 1 g of magnesiumribbon was placed, and in the other electrically heated boat made ofmolybdenum, 500 mg of indium was placed.

After the pressure of the vacuum chamber was decreased to 2×10⁻⁴ Pa,indium was vacuum deposited at a vacuum deposition speed of 0.03 to 0.08nm/sec and at the same time, from the other boat, magnesium was vacuumdeposited at a vacuum deposition speed of 1.7 to 2.8 nm/sec. Thetemperature of the boat containing indium was 800° C., and thetemperature of the boat containing magnesium was 500° C. Under the aboveconditions, a magnesium-indium mixed metal electrode was vacuumdeposited on the light emitting layer in a thickness of 150 nm in alaminated form to form the opposite electrode, thereby producing adevice.

Upon application of a DC voltage of 5 V onto the device obtained above,with the ITO electrode as a positive electrode and the magnesium-indiummixed metal electrode as a negative electrode, a current of about 6.3mA/cm² flew. The luminance of emitted light was 300 cd/m², and theemitted light was greenish blue in the chromaticity coordinates. Thewavelength of the peak was 486 nm. At this time, the luminous efficiencywas 2.9 lm/W. Furthermore, it was confirmed that when a DC voltage of 7V was applied, the luminance of emitted light was more than 1,000 cd/m².

EXAMPLE 27

A member comprising a 25 mm×75 mm×1.1 mm glass substrate and a 100 nmthick ITO film provided thereon by a vacuum deposition method(manufactured by HOYA Co., Ltd.) was used as a transparent substrate.

This transparent substrate was attached to a substrate holder of acommercially available vacuum deposition system (produced by ULVAC Co.,Ltd.). In an electrically heated boat made of molybdenum, 200 mg of TPDAwas placed, and in the other electrically heated boat made ofmolybdenum, 200 mg of the 2,5-xylenedimethylidyne derivative obtained inExample 8, 2,5-bis[2-phenyl-2-(2-naphthyl)vinyl]-xylene (NPVX) wasplaced. The pressure of the vacuum chamber was decreased to 1×10⁻⁴ Pa.

The boat containing TPDA was heated to 215° to 220° C., and TPDA wasvacuum deposited on the transparent substrate at a vacuum depositionspeed of 0.1 to 0.3 nm to form a 60 nm thick hole injection layer. Atthis time, the substrate temperature was room temperature.

Without taking the substrate out of the vacuum chamber, from the otherboat, NPVX was vacuum deposited on the hole injection layer in athickness of 80 nm in a laminated form as a light emitting layer. Inconnection with vacuum deposition conditions, the boat temperature was147° C., the vacuum deposition speed was 0.2 to 0.4 nm/sec, and thesubstrate temperature was room temperature.

The substrate was taken out of the vacuum chamber. A stainless steelmask was placed on the above light emitting layer and again attached tothe substrate holder.

Then, 1 g of magnesium ribbon was placed in an electrically heated boatmade of molybdenum, and in the other electrically heated boat made ofmolybdenum, 500 mg of indium was placed.

After the pressure of the vacuum chamber was decreased to 2×10⁻⁴ Pa,indium was vacuum deposited at a vacuum deposition speed of 0.03 to 0.08nm/sec, and at the same time, from the other boat, magnesium was vacuumdeposited at a vacuum deposition speed of 1.7 to 2.8 nm/sec. Thetemperature of the boat containing indium was 800° C., and thetemperature of the boat containing magnesium was 500° C. Under the aboveconditions, a magnesium-indium mixed metal electrode was vacuumdeposited on the light emitting layer in a thickness of 150 nm in alaminated form to form the opposite electrode, thereby producing adevice.

Upon application of a DC voltage of 17.5 V onto the device obtainedabove, with the ITO electrode as a positive electrode and themagnesium-indium mixed metal electrode as a negative electrode, acurrent of about 220 mA/cm² flew, and light emission of bluish green inthe chromaticity coordinates was obtained. The wavelength of the peakwas 502 nm as determined by spectral measurement. The luminance ofemitted light was 1,000 cd/m².

EXAMPLE 28

A member comprising a 25 mm×75 mm×1.1 mm glass substrate and a 100 nmthick ITO film provided thereon by a vacuum deposition method(manufactured by HOYA Co., Ltd.) was used as a transparent substrate.

This transparent substrate was attached to a substrate holder of acommercially available vacuum deposition system (manufactured by ULVACCo., Ltd.). Then, 200 mg of TPDA was placed in an electrically heatedboat made of molybdenum, and in the other boat made of molybdenum, 200mg of the 2,5 -xylenedimethylidyne derivative obtained in Example 10,2,5-bis[2-phenyl-2-(2-pyridyl)vinyl]xylene (PPVX), was place. Thepressure of the vacuum chamber was decreased to 1×10⁻⁴ Pa.

The above boat containing TPDA was heated to 215° to 220° C., and TPDAwas vacuum deposited on the transparent substrate at a vacuum depositionspeed of 0.1 to 0.3 nm/sec to form a 60 nm thick hole injection layer.At this time, the substrate temperature was room temperature.

Without taking the substrate out of the vacuum chamber, from the otherboat, PPVX was vacuum deposited on the hole injection layer in athickness of 80 nm in a laminated form as a light emitting layer. Inconnection with vacuum deposition conditions, the boat temperature was198° C., the vacuum deposition speed was 0.2 to 0.4 nm/sec, and thesubstrate temperature was room temperature.

The substrate was taken out of the vacuum chamber. A stainless steelmask was placed on the above light emitting layer and again attached tothe substrate holder.

Then, in an electrically heated boat made of molybdenum, 1 g ofmagnesium ribbon was placed, and in the other electrically heated boatmade of molybdenum, 500 mg of indium was placed.

After the pressure of the vacuum chamber was decreased to 2×10⁻⁴ Pa,indium was vacuum deposited at a vacuum deposition speed of 0.03 to 0.08nm/sec, and at the same time, from the other boat, magnesium was vacuumdeposited at a vacuum deposition speed of 1.7 to 2.8 nm/sec. Thetemperature of the boat containing indium was 800° C., and thetemperature of the boat containing magnesium was 500° C. Under the aboveconditions, a magnesium-indium mixed metal electrode was vacuumdeposited on the light emitting layer in a thickness of 150 nm in alaminated form to form the opposite electrode, thereby producing adevice.

Upon application of a DC voltage of 12.5 V onto the device obtainedabove, with the ITO electrode as a positive electrode and themagnesium-indium mixed metal electrode as a negative electrode, acurrent of about 50 mA/cm² flew, and light emission in green in thechromaticity coordinates was obtained. The wavelength of the peak was531 nm as determined by spectral measurement, and the luminance was 100cd/m².

EXAMPLE 29

A member comprising a 25 mm×75 mm×1.1 mm glass substrate and a 100 nmthick ITO film provided thereon by a vacuum deposition method(manufactured by HOYA Co., Ltd.) was used as a transparent substrate.

This transparent substrate was attached to a substrate holder of acommercially available vacuum deposition system (produced by ULVAC Co.,Ltd.). Then, 200 mg of TPDA was placed in an electrically heated boatmade of molybdenum, and in the other boat made of molybdenum, 200 mg ofthe 2,5-xylenedimethylidyne derivative obtained in Example 14,2,5-bis(2-phenyl-2-methylvinyl)xylene (MePVX), was placed. The pressureof the vacuum chamber was decreased to 1×10⁻⁴ Pa.

The above boat containing TPDA was heated to 215° to 220° C., and TPDAwas vacuum deposited on the transparent substrate at a vacuum depositionspeed of 0.1 to 0.3 nm/sec to form a 60 nm thick hole injection layer.At this time, the substrate temperature was room temperature.

Without taking the substrate out of the vacuum chamber, from the otherboat, MePVX was vacuum deposited on the hole injection layer in athickness of 80 nm in a laminated form as a light emitting layer. Inconnection with vacuum deposition conditions, the boat temperature was152° C., the vacuum deposition speed was 0.2 to 0.4 nm/sec, and thesubstrate temperature was room temperature. The substrate was taken outof the vacuum chamber. A stainless steel mask was placed on the abovelight emitting layer and again attached to the substrate holder.

Then, 1 g of magnesium ribbon was placed in an electrically heated boatmade of molybdenum, and in the other electrically heated boat made ofmolybdenum, 500 mg of indium was placed. Then, after the pressure of thevacuum chamber was decreased to 2×10⁻⁴ Pa, indium was vacuum depositedat a vacuum deposition speed of 0.03 to 0.08 nm/sec, and at the sametime, from the other boat, magnesium was vacuum deposited at a vacuumdeposition speed of 1.7 to 2.8 nm/sec. The temperature of the boatcontaining indium was 800° C., and the temperature of the boatcontaining magnesium was 500° C. Under the above conditions, amagnesium-indium mixed metal electrode was vacuum deposited on the lightemitting layer in a thickness of 150 nm in a laminated form to form theopposite electrode, thereby producing a device.

Upon application of a DC voltage of 10 V onto the device obtained above,with the ITO electrode as a positive electrode and the magnesium-indiummixed metal electrode as a negative electrode, a current of about 140mA/cm² flew, and purplish blue light emission in the chromaticitycoordinates was obtained. The wavelength of the peak was 438 nm asdetermined by spectral measurement, and the luminance of emitted lightwas about 20 cd/m².

EXAMPLE 30

A member comprising a 25 mm×75 mm×1.1 mm glass substrate and a 100 nmthick ITO film provided thereon by a vacuum deposition method(manufactured by HOYA Co., Ltd.) was used as a transparent substrate.This transparent substrate was subjected to UV ozone cleaning for 2minutes by the use of a UV ozone cleaning apparatus.

This transparent substrate was attached to a substrate holder of acommercially available vacuum deposition system (produced by ULVAC Co.,Ltd.). Then, 200 mg of TPDA was placed in an electrically heated boatmade of molybdenum, and in the other boat made of molybdenum, the4,4'-biphenylenedimethylidyne derivative obtained in Example 15,4,4'-bis(2-cyclohexyl-2-phenylvinyl)biphenyl (CPVBi), was placed. Thepressure of the vacuum chamber was decreased to 1×10⁻⁴ Pa.

The boat containing TPDA was heated to 215° to 220° C., and TPDA wasvacuum deposited on the transparent substrate at a vacuum depositionspeed of 0.1 to 0.3 nm/sec to form a 60 nm thick hole injection layer.At this time, the substrate temperature was room temperature.

Without taking the substrate out of the vacuum chamber, from the otherboat, CPVBi was vacuum deposited on the hole injection layer in athickness of 80 nm in a laminated form as a light emitting layer. Inconnection with vacuum deposition conditions, the boat temperature was210° C., the vacuum deposition speed was 0.1 to 0.3 nm/sec, and thesubstrate temperature was room temperature.

The substrate was taken out of the vacuum chamber. A stainless steelmask was placed on the above light emitting layer and again attached tothe substrate holder.

Then, 1 g of magnesium ribbon was placed in an electrically heated boatmade of molybdenum, and in the other electrically heated boat made ofmolybdenum, 500 mg of indium was placed.

After the pressure of the vacuum chamber was decreased, indium wasvacuum deposited at a vacuum deposition speed of 0.03 to 0.08 nm/sec,and at the same time, from the other boat, magnesium was vacuumdeposited at a vacuum deposition speed of 1.7 to 2.8 nm/sec. Thetemperature of the boat containing indium was 800° C., and thetemperature of the boat containing magnesium was 500° C. Under the aboveconditions, a magnesium-indium mixed metal electrode was vacuumdeposited on the light emitting layer in a thickness of 150 nm in alaminated form to form the opposite electrode, thereby producing adevice.

Upon application of a DC voltage of 7 V onto the device obtained above,with the ITO electrode as a positive electrode and the magnesium-indiummixed metal electrode as a negative electrode, a current of about 14mA/cm² flew, and light emission of purplish blue in the chromaticitycoordinates was obtained. The wavelength of the peak was 441 nm asdetermined by spectral measurement, and the luminance of emitted lightwas about 200 cd/m². The luminous efficiency was 0.64 lm/W.

EXAMPLE 31

A member comprising a 25 mm×75 mm×1.1 mm glass substrate and a 100 nmthick ITO film provided thereon by a vacuum deposition method(manufactured by HOYA Co., Ltd.) was used as a transparent electrode.This transparent electrode was subjected to UV ozone cleaning for 2minutes by the use of a UV ozone cleaning apparatus.

This transparent substrate was attached to a substrate holder of acommercially available vacuum deposition system (produced by ULVAC Co.,Ltd.). Then, 200 mg of TPDA was placed in an electrically heated boatmade of molybdenum, and in the other boat made of molybdenum, 200 mg ofthe 4,4'-biphenylenedimethylidyne derivative obtained in Example 16,4,4'-bis(2,2-di-p-tolylvinyl)biphenyl (DTVBi), was placed. The pressureof the vacuum chamber was decreased to 1×10⁻⁴ Pa.

The boat containing TPDA was heated to 215° to 220° C., and TPDA wasvacuum deposited on the transparent substrate at a vacuum depositionspeed of 0.1 to 0.3 nm/sec to form a hole injection layer with a filmthickness of 60 nm. At this time, the substrate temperature was roomtemperature.

Without taking the substrate out of the vacuum chamber, from the otherboat, DTVBi was vacuum deposited on the hole injection layer in athickness of 80 nm in a laminated form as a light emitting layer. Inconnection with vacuum deposition conditions, the boat temperature was253° to 271° C., the vacuum deposition speed was 0.1 to 0.3 nm/sec, andthe substrate temperature was room temperature. The substrate was takenout of the vacuum chamber. A stainless steel mask was placed on theabove light emitting layer and again attached to the substrate holder.

Then, 1 g of magnesium ribbon was placed in an electrically heated boatmade of molybdenum, and in the other electrically heated boat made ofmolybdenum, 500 mg of indium was placed.

After the pressure of the vacuum chamber was decreased to 2×10⁻⁴ Pa,indium was vacuum deposited at a vacuum deposition speed of 0.03 to 0.08nm/sec, and at the same time, from the other boat, magnesium was vacuumdeposited at a vacuum deposition speed of 1.7 to 2.8 nm. The temperatureof the boat containing indium was 800° C., and the temperature of theboat containing magnesium was 500° C. Under the above conditions, amagnesium-indium mixed metal electrode was vacuum deposited on the lightemitting layer in a thickness of 150 nm in a laminated form to form theopposite electrode, thereby producing a device.

Upon application of a DC voltage of 15 V onto the device obtained above,with the ITO electrode as a positive electrode and the magnesium-indiummixed metal electrode as a negative electrode, a current of about 32mA/cm² flew, and light emission of blue in the chromaticity coordinateswas obtained. The wavelength of the peak was 473 nm, and the maximumluminance of emitted light was more than 1,000 cd/m². The efficiency wasmore than 0.65 lm/W.

EXAMPLE 32

A member comprising a 25 mm×75 mm×1.1 mm glass substrate and a 100 nmthick ITO film provided thereon by a vacuum deposition method(manufactured by HOYA Co., Ltd.) was used as a transparent substrate.This transparent substrate was subjected to UV ozone cleaning for 2minutes by the use of a UV ozone cleaning apparatus.

This transparent substrate was attached to a substrate holder of acommercially available vacuum deposition system (produced by ULVAC Co.,Ltd.). Then, 200 mg of TPDA was placed in an electrically heated boatmade of molybdenum, and in the other boat made of molybdenum, 200 mg ofthe 2,6-naphthylenedimethylidyne derivative obtained in Example 18,2,6-bis(2,2-di-p-tolylvinyl)naphthalene (DTVN), was placed. The pressureof the vacuum chamber was decreased to 1×10⁻⁴ Pa.

The boat containing TPDA was heated to 215° to 220° C., and TPDA wasvacuum deposited on the transparent substrate at a vacuum depositionspeed of 0.1 to 0.3 nm/sec to form a 60 nm thick hole injection layer.At this time, the substrate temperature was room temperature.

Without taking the substrate out of the vacuum chamber, from the otherboat, DTVN was vacuum deposited on the hole injection layer in athickness of 80 nm in a laminated form as a light emitting layer. Inconnection with vacuum deposition conditions, the boat temperature was276° to 278° C., the vacuum deposition speed was 0.1 to 0.3 nm/sec, andthe substrate temperature was room temperature. The substrate was takenout of the vacuum chamber. A stainless steel mask was placed on theabove light emitting layer and again attached to the substrate holder.

Then, 1 g of magnesium ribbon was placed in an electrically heated boatmade of molybdenum, and in the other electrically heated boat made ofmolybdenum, 500 mg of indium was placed.

After the pressure of the vacuum chamber was decreased to 2×10⁻⁴ Pa,indium was vacuum deposited at a vacuum deposition speed of 0.03 to 0.08nm/sec, and at the same time, from the other boat, magnesium was vacuumdeposited at a vacuum deposition speed of 1.7 to 2.8 nm/sec. Thetemperature of the boat containing indium was 800° C., and thetemperature of the boat containing magnesium was 500° C. Under the aboveconditions, a magnesium-indium mixed metal electrode was vacuumdeposited on the light emitting layer in a thickness of 150 nm in alaminated form to form the opposite electrode, thereby producing adevice.

Upon application of a DC voltage of 12 V onto the device obtained above,with the ITO electrode as a positive electrode and the magnesium-indiummixed metal electrode as a negative electrode, a current of about 350mA/cm² flew, and light emission of greenish blue in chromaticitycoordinates was obtained. The wavelength of the peak was 486 nm asdetermined by spectral measurement, and the luminance of emitted lightwas 20 cd/m².

EXAMPLE 33

A member comprising a 25 mm×75 mm×1.1 mm glass substrate and a 100 nmthick ITO film provided thereon by a vacuum deposition method(manufactured by HOYA Co., Ltd.) was used as a transparent substrate.This transparent substrate was subjected to UV ozone cleaning for 2minutes by the use of a UV ozone cleaning apparatus.

This transparent substrate was attached to a substrate holder of acommercially available vacuum deposition system (produced by ULVAC Co.,Ltd.). Then, 200 mg of TPDA was placed in an electrically heated boatmade of molybdenum, and in the other boat made of molybdenum, 200 mg ofthe 9,10-anthracenedimethylidyne derivative obtained in Example 19,9,10-bis(2,2-di-p-tolylvinyl)anthracene (DTVA), was placed. The pressureof the vacuum chamber was decreased to 1×10⁻⁴ PA.

The boat containing TPDA was heated to 215° to 220° C., and TPDA wasvacuum deposited on the transparent substrate at a vacuum depositionspeed of 0.1 to 0.3 nm/sec to form a 60 nm thick hole injection layer.At this time, the substrate temperature was room temperature.

Without taking the substrate out of the vacuum chamber, from the otherboat, DTVA was vacuum deposited on the hole injection layer in athickness of 80 nm in a laminated form as a light emitting layer. Inconnection with vacuum deposition conditions, the boat temperature was270° C., the vacuum deposition speed was 0.1 to 0.3 nm/sec, and thesubstrate temperature was room temperature. The substrate was taken outof the vacuum chamber. A stainless steel mask was placed on the lightemitting layer and again attached to the substrate holder.

Then, 1 g of magnesium ribbon was placed in an electrically heated boatmade of molybdenum, and in the other electrically heated boat made ofmolybdenum, 500 mg of indium was placed. After the pressure of thevacuum chamber was decreased to 2×10⁻⁴ Pa, indium was vacuum depositedat a vacuum deposition speed of 0.03 to 0.08 nm/sec, and at the sametime, from the other boat, magnesium was vacuum deposited at a vacuumdeposition speed of 1.7 to 2.8 nm/sec. The temperature of the boatcontaining indium was 800° C., and the temperature of the boatcontaining magnesium was 500° C. Under the above conditions, amagnesium-indium mixed metal electrode was vacuum deposited on the lightemitting layer in a thickness of 150 nm in a laminated form to form theopposite electrode, thereby producing a device.

Upon application of a DC voltage of 10 V onto the device obtained above,with the ITO electrode as a positive electrode and the magnesium-indiummixed metal electrode as a negative electrode, a current of about 350mA/cm² flew, and light emission of green in the chromaticity coordinateswas obtained. The wavelength of the peak was 526 nm as determined byspectral measurement, and the luminance of emitted light was more than400 cd/m².

EXAMPLE 34

A member comprising a 25 mm×75 mm×1.1 mm glass substrate and a 100 nmthick ITO film provided thereon by a vacuum deposition method was usedas a transparent substrate.

This transparent substrate was attached to a substrate holder of acommercially available vacuum deposition system (manufactured by ULVACCo., Ltd.). Then, 200 mg of TPDA was placed in an electrically heatedboat made of molybdenum, and in the other boat made of molybdenum, 200mg of DPVB was placed. The pressure of the vacuum chamber was decreasedto 1×10⁻⁴ Pa.

The boat containing TPDA was heated to 215° to 220° C., and TPDA wasvacuum deposited on the transparent substrate at a vacuum depositionspeed of 0.1 to 0.3 nm/sec to form a 75 nm thick hole injection layer.At this time, the substrate temperature was room temperature.

Without taking the substrate out of the vacuum chamber, from the otherboat, DPVB was vacuum deposited on the hole injection layer in athickness of 60 nm in a laminated form as a light emitting layer. Inconnection with vacuum deposition conditions, the boat temperature was152° to 153° C., the vacuum deposition speed was 0.1 to 0.2 nm/sec, andthe substrate temperature was room temperature.

The substrate was taken out of the vacuum chamber. A stainless steelmask was placed on the light emitting layer and again attached to thesubstrate holder. Then, 1 g of magnesium ribbon was placed in anelectrically heated boat made of molybdenum, and as an electron guntarget for electron beam vacuum deposition, positioned under thesubstrate holder in the central part of the vacuum chamber, copperpellets were placed. After the pressure of the vacuum chamber wasdecreased to 2×10⁻⁴ Pa, copper was vacuum deposited at a vacuumdeposition speed of 0.03 to 0.08 nm/sec by an electron beam vacuumdeposition method, and at the same time, from the molybdenum boat,magnesium was vacuum deposited at a vacuum deposition speed of 1.7 to2.8 nm/sec by an electrically heating method. At this time, the emissioncurrent of a filament of the electron gun was 200° to 30 mA, theacceleration voltage was 4 kV, and the boat temperature was about 500°C. Under the above conditions, a magnesium-copper mixed metal electrodewas vacuum deposited on the light emitting layer in a thickness of 70 nmin a laminated form to form the opposite electrode.

Upon application of a DC voltage of 19 V on the EL device producedabove, with the ITO electrode as a positive electrode and themagnesium-copper mixed metal electrode as a negative electrode, acurrent of 91 mA/cm² flew, and light emission of bluish green wasobtained. The wavelength of the peak was 491 nm as determined byspectral measurement, and the luminance of the emitted light was 880cd/m².

The light emission was uniformly in the plane light emission, and it wasconfirmed that there were no pin holes in the light emitting layer.Moreover, light emission was greatly stabilized.

EXAMPLE 35

A member comprising a 25 mm×75 mm×1.1 mm glass substrate and a 100 nmthick ITO film provided thereon by a vacuum deposition method was usedas a transparent substrate.

This transparent substrate was attached to a substrate holder of acommercially available vacuum deposition system (manufactured by ULVACCo., Ltd.). Then, 200 mg of TPDA was placed in an electrically heatedboat made of molybdenum, and in the other boat made of molybdenum, 200mg of 1,4-bis(2-p-methylphenyl-2-biphenylvinyl)benzene (MPVB) wasplaced. The pressure of the vacuum chamber was decreased to 1×10⁻⁴ Pa.Then the boat containing TPDA was heated to 215° to 220° C., and TPDAwas vacuum deposited on the transparent substrate at a vacuum depositionspeed of 0.1 to 0.3 nm/sec to form a 75 nm thick hole injection layer.At this time, the substrate temperature was room temperature.

Without taking the substrate out of the vacuum chamber, from the otherboat, MPVB was vacuum deposited on the hole injection layer in athickness of 60 nm in a laminated form as a light emitting layer. Inconnection with vacuum deposition conditions, the boat temperature was180° to 190° C., the vacuum deposition speed was 0.1 to 0.2 nm/sec, andthe substrate temperature was room temperature.

The substrate was taken out of the vacuum chamber. A stainless steelmask was placed on the light emitting layer and again attached to thesubstrate holder. Then, 1 g of magnesium ribbon was placed in anelectrically heated boat made of molybdenum, and as an electron guntarget for electron beam vacuum deposition as positioned under thesubstrate holder in the central part of the vacuum chamber, copperpellets were placed. Then, after the pressure of the vacuum chamber wasdecreased to 2×10⁻⁴ Pa, copper was vacuum deposited at a vacuumdeposition speed of 0.03 to 0.08 nm/sec by an electron beam vacuumdeposition method, and at the same time, from the molybdenum boat,magnesium was vacuum deposited at a vacuum deposition speed of 1.7 to2.8 nm/sec by an electrically heating method. At this time, the emissioncurrent of a filament of the electron gun was 200 to 230 mA, theacceleration voltage was 4 kV, and the boat temperature was about 500°C. Under the above conditions, a magnesium-copper mixed metal electrodewas vacuum deposited on the light emitting layer in a thickness of 70 nmin a laminated form to form the opposite electrode.

Upon application of a DC voltage of 20 V onto the EL device obtainedabove, with the ITO electrode as a positive electrode and themagnesium-copper mixed metal electrode as a negative electrode, acurrent of 238 mA/cm² flew, and light emission of green was obtained.The wavelength of the peak was 512 nm as determined by spectralmeasurement, and the luminance of emitted light was 1,100 cd/m².

As in Example 34, light emission was uniform in the light emissionplane, and the light of green was greatly stabilized.

EXAMPLE 36

A member comprising a 25 mm×75 mm×1.1 mm glass substrate and a 100 nmthick ITO film provided thereon by a vacuum deposition method was usedas a transparent substrate.

This transparent substrate was attached to a substrate holder of acommercially available vacuum deposition system (manufactured by ULVACCo., Ltd.). Then, 200 mg of TPDA was placed in an electrically heatedboat made of molybdenum, and in the other boat made of molybdenum, 200mg of DTVB obtained in Example 1 was placed. The pressure of the vacuumchamber was decreased to 1×10⁻⁴ Pa. The boat containing TPDA was heatedto 215° to 220° C., and TPDA was vacuum deposited on the transparentsubstrate at a vacuum deposition speed of 0.1 to 0.3 nm/sec to form a 70nm thick hole injection layer. At this time, the substrate temperaturewas room temperature.

Without taking the substrate out of the vacuum chamber, from the otherboat, DTVB was vacuum deposited on the hole injection layer in athickness of 60 nm in a laminated form as a light emitting layer. Inconnection with vacuum deposition conditions, the boat temperature was237° to 238° C., the vacuum deposition speed was 0.1 to 0.2 nm/sec, andthe substrate temperature was room temperature.

The substrate was taken out of the vacuum chamber. A stainless steelmask was placed on the light emitting layer and again attached to thesubstrate holder. Then, 1 g of magnesium ribbon was placed in anelectrically heated boat, and as an electron gun target for electronbeam vacuum deposition as posited under the substrate holder in thecentral part of the vacuum chamber, copper pellets were placed. Thepressure of the vacuum chamber was decreased to 2×10⁻⁴ Pa. Then, copperwas vacuum deposited at a vacuum deposition speed of 0.03 to 0.08 nm/secby an electron beam vacuum deposition method, and at the same time, fromthe molybdenum boat, magnesium was vacuum deposited at a vacuumdeposition speed of 1.7 to 2.8 nm/sec. At this time, the emissioncurrent of a filament of the electron gun was 200° to 230 mA, theacceleration voltage was 4 kV, and the boat temperature was about 500°C. Under the above conditions, a magnesium-copper mixed metal electrodewas vacuum deposited on the light emitting layer in a thickness of 70 nmin a laminated form to form the opposite electrode.

Upon application of a DC voltage of 20 V onto the EL device obtainedabove, with the ITO electrode as a positive electrode and themagnesium-copper mixed metal electrode as a negative electrode, acurrent of 119 mA/cm² flew, and light emission of bluish green wasobtained. The wavelength of the peak was 487 nm as determined byspectral measurement, and the luminance of the emitted light was 980cd/m².

The emitted light was uniform in the emitted light plane and was greatlystable.

EXAMPLE 37

A member comprising a 25 mm×75 mm×1.1 mm glass substrate and a 100 nmthick ITO film provided thereon by a vacuum deposition method was usedas a transparent substrate.

This transparent substrate was attached to a substrate holder of acommercially available vacuum deposition system (manufactured by ULVACCo., Ltd.). Then, 200 mg of TPDA was placed in an electrically heatedboat made of molybdenum, and in the other boat made of molybdenum, 200mg of DPVB was placed. Then the pressure of the vacuum chamber wasdecreased to 1×10⁻⁴ Pa. The above boat containing TPDA was heated to215° to 220° C., and TPDA was vacuum deposited on the transparentsubstrate at a vacuum deposition speed of 0.1 to 0.3 nm/sec to form a 60nm thick positive hole injection layer. At this time, the substratetemperature was room temperature.

Then, in the same manner as in Example 34, DPVB was laminated.

The pressure of the vacuum chamber was returned to atmospheric pressure,and the two boats made of molybdenum were taken out of the vacuumchamber. Instead, a molybdenum boat containing 200 mg of[3",4":3,4,5:10",9":3',4',5']-dipyridyno[1,2-a:1',2'-a]bisbenzoimidazole-6,18-dionewas placed in the vacuum chamber. Then the pressure of the vacuumchamber was decreased to 2×10⁻⁴ Pa. The above boat was heated to 500° C.and the above substance was vacuum deposited on the light emitting layerin a thickness of 60 nm in a laminated form as an electron injectionlayer.

The pressure of the vacuum chamber was returned to atmospheric pressure.After removal of the above laminated sample from the substrate holder, astainless steel mask was placed and then attached to the substrateholder. Then, 1 g of magnesium ribbon was placed in an electricallyheated boat made of molybdenum, and as an electron gun target forelectron beam vacuum deposition as positioned below the substrate holderin the central part of the vacuum chamber, a copper pellet was placed.After the pressure of the vacuum chamber was decreased to 2×10⁻⁴ Pa,copper was vacuum deposited at a vacuum deposition speed of 0.03 to 0.08nm/sec by the electron beam vacuum deposition method, and at the sametime, magnesium was vacuum deposited at a vacuum deposition speed of 1.7to 2.8 nm/sec by the electrically heating method. At this time, theemission current of a filament of the electron gun was 200 to 230 mA,the acceleration voltage was 4 kV, and the temperature of the boat wasabout 500° C. Under the above conditions, a magnesium-copper mixed metalelectrode was vacuum deposited on the light emitting layer in athickness of 100 nm in a laminated form to form the opposite electrode.

Upon application of a DC voltage of 19 V onto the EL device aboveproduced, with the ITO electrode as a positive electrode and themagnesium-copper mixed metal electrode as a negative electrode, acurrent of about 100 mA/cm² flew, and the same bluish green light as inExample 34 was emitted. The wavelength of the peak was 490 nm asdetermined by spectral measurement, and the luminance was 1,000 cd/m².

The luminous state was uniform and greatly stabilized as in Example 34.

What is claimed is:
 1. An electroluminescence device comprising a lightemitting material placed between a pair of electrodes, wherein the lightemitting material comprises a compound represented by the formula:##STR53## wherein R¹ and R² are each an alkyl group, an unsubstitutedcyclohexyl group; a cyclohexyl group substituted by at least onesubstituent selected from the group consisting of an alkyl group, analkoxy group, or a phenyl group; an alkoxy group; a cyano group; anunsubstituted aryl group; an aryl group substituted with at least onesubstituent (a) selected from the group consisting of an alkyl group, analkoxy group, an acyl group, an acyloxy group, an acyl amino group, anaralkyl group, an aryloxy group, a cyano group, a carboxyl group, avinyl group, a styryl group, an aminocarbonyl group, an aryloxycarbonylgroup, a hydroxyl group, an alkoxycarbonyl group, a halogen group and anamino group, wherein the substituents together may form a 5-membered or6-members ring; R³ and R⁴ are each an unsubstituted heterocyclic group,a heterocyclic group substituted by at least one substituent (a) asdefined above, an unsubstituted aryl group or aryl group substituted byat least one substituent (a) as defined above, Ar is an unsubstitutedarylene group or an arylene group substituted by a substituent selectedfrom the group a cyano group, a carboxyl group, an aminocarbonyl group,a carbamoyl group, an aranyl group, a hydroxyl group, an aryloxycarbonylgroup, a methoxycarbonyl group, an ethoxycarbonyl group, abutoxycarbonyl group and an amino group, wherein the substituentstogether may form a saturated 5-members or 6-membered ring, and R¹ andR³, and R² and R⁴ may combine together to form a saturated orunsaturated ring structure.
 2. The electroluminescence device as claimedin claim 1, wherein the compound is represented by the formula:##STR54## wherein X and Y may be the same or different and are each analkyl group having 1 to 4 carbon atoms, a phenyl group, a substitutedphenyl group, a cyclohexyl group, a substituted cyclohexyl group, anaphthyl group, a substituted naphthyl group, a pyridyl group or asubstituted pyridyl group, wherein the substituted phenyl group, thesubstituted cyclohexyl group, the substituted naphthyl group and thesubstituted pyridyl group are substituted by a substituent which is analkoxy group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4carbon atoms, or a phenyl group, and each substituted group may besubstituted by a plurality of said substituent groups, and Ar' is##STR55##
 3. The electroluminescence device as claimed in claim 2wherein X and Y are each a methyl group, a naphthyl group, a pyridylgroup, a cyclohexyl group, a tolyl group, a methoxyphenyl group, or abiphenyl group.
 4. The electroluminescence device as claimed in claims 1or 2, further comprising laminated in the following order: a positiveelectrode, a hole injection layer, a light emitting layer comprisingsaid light emitting material, and a negative electrode.
 5. Theelectroluminescence device as claimed in claims 1 or 2 furthercomprising laminated in the following order a positive electrode, a holeinjection layer, a light emitting layer comprising said light emittingmaterial, an electron injection layer, and a negative electrode.
 6. Theelectroluminescence device as claimed in claim 2, wherein said compoundis ##STR56##
 7. The electroluminescence device as claimed in claim 2,wherein said compound is ##STR57##
 8. The electroluminescence device asclaimed in claim 2, wherein said compound is ##STR58##
 9. Theelectroluminescence device as claimed in claim 2, wherein said compoundis ##STR59##
 10. The electroluminescence device as claimed in claim 2,wherein said compound is ##STR60##
 11. The electroluminescence device asclaimed in claim 2, wherein said compound is ##STR61##
 12. Theelectroluminescence device as claimed in claim 2, wherein said compoundis ##STR62##
 13. The electroluminescence device as claimed in claim 2,wherein said compound is ##STR63##
 14. The electroluminescence device asclaimed in claim 2, wherein said compound is ##STR64##
 15. Theelectroluminescence device as claimed in claim 2, wherein said compoundis ##STR65##
 16. The electroluminescence device as claimed in claim 2,wherein said compound is ##STR66##
 17. The electroluminescence device asclaimed in claim 2, wherein said compound is ##STR67##
 18. Theelectroluminescence device as claimed in claim 2, wherein said compoundis ##STR68##
 19. The electroluminescence device as claimed in claim 1,wherein the electrode are electrode layers.
 20. The electroluminescencedevice as claimed in claim 4, further comprising an electron injectionlayer disposed between the light emitting layer and the negativeelectrode.
 21. The electroluminescence device as claimed in claim 5,further comprising an electron injection layer disposed between thelight emitting layer and the negative electrode.
 22. Theelectroluminescence device as claimed in claim 1, wherein Ar is aphenylene group or a biphenylene group.
 23. An electroluminescencedevice as claimed in claim 1, wherein R¹ and R² are each a methyl group;and ethyl group; a propyl group; a butyl group; an unsubstitutedcyclohexyl group; a cyclohexyl group substituted by at least onesubstituent selected from the group consisting of an alkyl group having1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms and aphenyl group; a methoxy group; an ethoxy group; a propoxy group; abutoxy group; a cyano group; an unsubstituted phenyl; an unsubstitutednaphthyl; an unsubstituted anthranyl; or a phenyl, naphthyl or anthranylgroup substituted by a substituent (a) selected from the groupconsisting of a halogen atom, an ethyl group, a propyl group, a butylgroup, a methoxy group, an ethoxy group, a propoxy group, a butoxygroup, a formyl group, a propionyl group, a butylyl group, an acetyloxygroup, a propionylamino group, a butylylamino group, a phenoxy group, atolyloxy group, a cyano group, a carboxyl group, a vinyl group, a styrylgroup, an anilinocarbonyl group, a dimethylamonocarbonyl group, acarbamoyl group, an aranyl group, a hydroxyl group, anaphthyloxycarbonyl group, a xylyloxycarbonyl group, a phenoxycarbonylgroup, a methoxycarbonyl group, an ethoxycarbonyl group, abutoxycarbonyl group, and an amino group represented by the formula:##STR69## wherein R⁵ and R⁴ are each a hydrogen atom, a methyl group, anethyl group, a propyl group or a butyl group, a formyl group, apropionyl group, an aldehyde group, an unsubstituted phenyl group, atolyl group, a xylyl group, or R⁵ and R⁶ together form a 5-membered or6-membered ring,R³ and R⁴ are each an unsubstituted phenyl,unsubstituted naphthyl, unsubstituted anthranyl, unsubstituted pyridylgroup, unsubstituted oxazolyl group, unsubstituted thienyl group,unsubstituted imidazolyl group, unsubstituted thiazolyl group,unsubstituted benzoimidazolyl group, unsubstituted benzothiazolyl group,unsubstituted pyrazolyl group, unsubstituted triazolyl group,unsubstituted monovalent group comprising pyridone, unsubstitutedfuraryl group, unsubstituted benzoxazolyl group, or unsubstitutedquinolyl group, or a phenyl, naphthyl, anthranyl, a pyridyl group, anoxazolyl group, a thienyl group, an imidazolyl group, a thiazolyl group,a benzoimidazolyl group, a benzothiazolyl group, a pyrazolyl group, atriazolyl group, a monovalent group comprising pyridone, a furarylgroup, a benzoxazolyl group, or a quinolyl group substituted by one ormore of said substituents (a), Ar is an unsubstituted arylene group oran arylene group substituted by a halogen atom, a methyl group, an ethylgroup, a propyl group, a butyl group, a cyclohexyl group, a methoxygroup, an ethoxy group, a propoxy group, a butoxy group, a formyl group,a propionyl group, a butyryl group, an acetyloxy group, a propionylaminogroup, a butylylamino group, a benzyl group, a phenethyl group, aphenoxy group, a tolyloxy group, a cyano group, a carboxyl group, ananilinocarbonyl group, a dimethylamonocarbonyl group, a carbamoyl group,an aranyl group, a hydroxyl group, a phenoxycarbonyl group, anaphthyloxycarbonyl group, a xylyloxycarbonyl group, a methoxycarbonylgroup, an ethoxycarbonyl group, a butoxycarbonyl group, and an aminogroup of said formula (I).
 24. The electroluminescence device as claimedin claim 2, wherein X and Y are the same or different and each is amethyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl,tert-butyl, unsubstituted phenyl, unsubstituted cyclohexyl,unsubstituted naphthyl or unsubstituted pyridyl, tolyl, dimethylphenyl,ethylphenyl, methoxyphenyl, ethoxyphenyl, biphenyl, methylcyclohexyl,dimethylcyclohexyl, ethylcyclohexyl, methoxycyclohexyl,ethoxycyclohexyl, phenylcyclohexyl, methylnaphthyl, dimethylnaphthyl,methoxynaphthyl, ethoxynaphthyl, methyl pyridyl, phenyl-unsubstitutednaphthyl, dimethylpyridyl, ethylpyridyl, methoxypyridyl, ethoxypyridylor phenyl-substituted pyridyl.
 25. An electroluminescence devicecomprising a light emitting material placed between a pair of electrodeswherein the light emitting material comprises a compound represented bythe formula: ##STR70## wherein R¹ and R² are each an alkyl group, acyclohexyl group; an alkoxy group; a cyano group; an unsubstituted arylgroup; an aryl group substituted with at least one substituent (a)selected from the group consisting of an alkyl group, an alkoxy group,an acyl group, an acyloxy group, an acyl amino group, an aralkyl group,an aryloxy group, a cyano group, a carboxyl group, a vinyl group, astyryl group, an aminocarbonyl group, an aryloxycarbonyl group, ahydroxyl group, an alkoxycarbonyl group, a halogen group and an aminogroup, wherein the substituents together may form a 5-membered or6-members ring; R³ and R⁴ are each an unsubstituted heterocyclic group,a heterocyclic group substituted by at least one substituent (a) asdefined above, an unsubstituted aryl group or aryl group substituted byat least one substituent (a) as defined above, Ar is an unsubstitutedarylene group or an arylene group substituted by a substituent selectedfrom the group consisting of a halogen atom, an alkyl group, an alkoxygroup, an acyl group, an acyloxy group, an aralkyl group, an aryloxygroup, a cyano group, a carboxyl group, an aminocarbonyl group, acarbamoyl group, an aranyl group, a hydroxyl group, an aryloxycarbonylgroup, a methoxycarbonyl group, an ethoxycarbonyl group, abutoxycarbonyl group and an amino group, wherein the substituentstogether may form a saturated 5-members or 6-membered ring, and R¹ andR³, and R² and R⁴ may combine together to form a saturated orunsaturated ring structure.
 26. The electroluminescence device asclaimed in claim 1, wherein the compound is selected from the groupconsisting of ##STR71##
 27. The electroluminescence device as claimed inclaim 1, wherein the compound is represented by the formula: ##STR72##wherein X and Y may be the same or different and are each an alkyl grouphaving 1 to 4 carbon atoms, a phenyl group, a substituted phenyl group,a cyclohexyl group, a substituted cyclohexyl group, a naphthyl group, asubstituted naphthyl group, a pyridyl group or a substituted pyridylgroup, wherein the substituted phenyl group, the substituted cyclohexylgroup, the substituted naphthyl group and the substituted pyridyl groupare substituted by a substituent which is an alkoxy group having 1 to 4carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a phenylgroup, and each substituted group may be substituted by a plurality ofsaid substituent groups, and Ar' is ##STR73##
 28. Theelectroluminescence device as claimed in claim 27, wherein said compoundis ##STR74##
 29. The electroluminescence device as claimed in claim 27,wherein said compound is ##STR75##
 30. The electroluminescence device asclaimed in claim 27, wherein said compound is ##STR76##
 31. Theelectroluminescence device as claimed in claim 27, wherein said compoundis ##STR77##
 32. The electroluminescence device as claimed in claim 27,wherein said compound is ##STR78##